Do the following in your exercise book:

1. Draw an arc using a radius of 3 cm.

2. Draw an arc bigger than a quarter circle, using a radius of 5 cm.

3. Draw an arc smaller than a quarter circle, using a radius of 5 cm.

Enrichment

Familiar figures in the seven-circle pattern

For this activity you need five seven-circle sets like the ones drawn in the previous two activities. Start by drawing these on blank pieces of paper. Don't make your radius bigger than 4 cm. Number your sets figure 2 to figure 6. Label each figure as shown on the right.

1. Follow the instructions below.

   • Figure 1: Use the figure alongside. Draw lines connecting AB, BC, CD,. . . up to FA.
   • Figure 2: Draw lines connecting A, O and B.
   • Figure 3: Draw lines connecting B, F and D.
   • Figure 4: Draw lines connecting BC, CE, EF and FB.
   • Figure 5: Draw lines connecting CD, DE, EF and FC.
   • Figure 6: Draw lines connecting AB, BC, CE and EA.

2. Complete the table below.

   It shows the name of each figure and its properties.

   Figure 1 (on the right) has been done as an example.

   

   Figure	Name of figure	Properties
   1	Regular hexagon	6-sided figure. All the sides are equal. All the interior angles are equal.
   2
   3
   4
   5
   6

Construct some more figures

Read the instructions carefully and follow them exactly.

1. 1. Draw a line in your exercise book. The line should be between 3 and 6 cm long. Draw it in the middle of your page.

   2. Label the ends A and B.

   3. Place the point of your compass at point A. Carefully set the radius of your compass to the distance between A and B.

   4. Draw a circle with the compass point at A.

   5. Draw another circle with the compass point at B without changing the radius width.

   6. The circles cross at two points. Choose one of these points. Label it C. Check that you are on the right track by comparing your sketch to the one on the right.

   7. Carefully rule the lines AC and BC.

   8. What sort of figure is ABC? Check this by measuring angles. Why do you think this happened?

      

      ---

2. 1. Draw two lines PQ and QR in your exercise book.

      • The lines meet and form an angle at Q.
      • You can make your angle any size.
      • Make your line lengths different.
      • Do not make your lines longer than 6 cm each.

      • Place your compass point at point Q. Set the radius of your compass to the distance QP. Place the compass point at R. Draw a circle.

        

      • Place the compass point back at Q. Set the radius to the length QR. Place the compass point at P. Draw a circle.

      • The two circles cross at two points. Decide which point will be the vertex of a parallelogram. Call this point S.

        

      • Join the lines SP and SR. Is PQRS a parallelogram?

        ---

Parallel and perpendicular lines with circles

Parallel and perpendicular

1. Revision: Complete these definitions.

   1. When one line is parallel to another line, the lines

      ---

   2. When one line is perpendicular to another line, the lines

      ---

2. A seven-circle figure has been drawn below. The intersection points have been marked. A line segment has been drawn in. Use a ruler and pencil to join pairs of points so that the lines are:

   1. parallel to the line segment

   2. perpendicular to the line segment.

   

   When two lines (or arcs) cross each other we say they intersect.

   The intersection point is the place where they meet.

   You should have drawn 7 lines (2 parallel and 5 perpendicular to the line segment).Compare your lines with a friend's lines. Do you agree?

3. In your exercise book, draw a few circles with the same radius along a line. Start by drawing a line. Then use your compass to draw a circle with the midpoint on the line.

   

   Keep your compass the same width and draw another circle with the centre where the first circle crossed the line. Repeat as many times as you wish. In the example at the bottom of the previous page only three circles have been drawn.

   1. Can you find that example in the seven-circle figure? Look carefully until you see it.

   2. Can you see where you can construct lines that are perpendicular to the given line? Draw them carefully with a pencil and your ruler.

   3. Can you see the two lines that are parallel to the given line? Draw them in too.

4. Use circles to construct a line that is perpendicular to the line below.

   

5. Use circles to construct a line that is parallel to the line below.

   

Extension

Geometry of shapes

In this chapter, you will learn about different kinds of 2D shapes. You will learn the names given to different shapes. You will also learn about the different properties that different types of shapes have in relation to their sides and angles.

Triangles, quadrilaterals, circles and others

Decide which is which and draw some figures

1. Which shapes on the opposite page are circles?

   ---

2. Which shapes on the opposite page are triangles?

   ---

3. Which shapes on the opposite page are quadrilaterals?

   ---

   Use your ruler to do the following:

4. Make a drawing of one triangle with three acute angles, and another triangle with one obtuse angle.

5. 1. Draw a quadrilateral with two obtuse angles.

      ---

   2. Can you draw a triangle with two obtuse angles?

      ---

6. 1. Draw a triangle with one right angle, and a triangle without any right angles.

   2. Can you draw a triangle with two right angles?

   3. Can you draw a quadrilateral with four right angles?

7. These four lines form quadrilateral ABCD.

   

   The two red sides, BC and AD, are called opposite sides of quadrilateral ABCD.

   Which other two sides of ABCD are also opposite sides?

   ---

8. The lines DA and AB in the figure in question 7 are called adjacent sides. They meet at a point that is one of the vertices (corner points) of the quadrilateral.

   1. Name another two adjacent sides in ABCD.

      ---

   2. AB is adjacent to DA in the quadrilateral ABCD. Which other side of ABCD is also adjacent to DA?

      ---

9. William says:

   "Each side of a quadrilateral has two adjacent sides.

   Each side of a quadrilateral also has two opposite sides."

   Is William correct? Give reasons for your answer.

   ---

10. William also says:

    "In a triangle, each side is adjacent to all the other sides."

    Is this true? Give a reason for your answer.

    ---

11. In each case, say whether the two sides are opposite sides or adjacent sides of the quadrilateral PQRS.

    

    1. QP and PS

       ---

    2. QP and SR

       ---

    3. PQ and RQ

       ---

    4. PS and QR

       ---

    5. SR and QR

       ---

Different types of triangles

Equilateral, isosceles, scalene and right-angled triangles

1. Measure every angle in each of the isosceles triangles given above. Do you notice anything special? If you are not sure, draw more isosceles triangles in your exercise book.

   ---

2. Measure the angles and sides of the following triangles. What is special about these triangles? In other words, what makes these triangles different to other triangles?

   

   ---

   These triangles are called equilateral triangles.

3. 1. Measure each angle in each of the following triangles. Do you notice anything special about these angles?

      

      ---

   2. Identify the longest side in each of the triangles. If you are not sure which one is the longest side, measure the sides. What do you notice about the longest side in each of these triangles?

      ---

Comparing and describing triangles

When two or more sides of a shape are equal in length, we show this using short lines on the equal sides.

1. Use the following triangles to answer the questions that follow:

   

   

   1. Which triangle has only two sides that are equal?

      ---

      What is this type of triangle called?

      ---

   2. Which triangle has all three sides equal?

      ---

      What is this type of triangle called?

      ---

   3. Which triangle has an angle equal to 90°?

      ---

      What is this type of triangle called?

      ---

2. Write down the type of each of the following triangles in the space provided:

Finding unknown sides in triangles

1. 1. Name each type of triangle below.

      

      ---

      

      ---

      

      ---

   2. Use the given information to determine the length of the following sides:

      AB:

      ---

      BC:

      ---

      EF:

      ---

   3. Can you determine the lengths of GH and HI? Explain your answer.

      ---

2. The square in the corner of \(\triangle\)JKL shows that it is a right angle. Give a reason for each of your answers below.

   

   1. Is this triangle scalene, isosceles, or equilateral?

      ---

   2. Name the two sides of the triangle that are equal.

      ---

   3. What is the length of JK?

      ---

   4. Name two equal angles in this triangle.

      ---

   5. What is the size of \(\hat{J}\) and \(\hat{L}\) ?

      ---

Different types of quadrilaterals

Investigating quadrilaterals

1. The two pages that follow show different groups of quadrilaterals.

   1. In which groups are both pairs of opposite sides parallel?

      ---

   2. In which groups are only some adjacent sides equal?

      ---

   3. In which groups are all four angles equal?

      ---

   4. In which groups are all the sides in each quadrilateral equal?

      ---

   5. In which groups are all four sides equal?

      ---

   6. In which groups is each side perpendicular to the sides adjacent to it?

      ---

   7. In which groups are opposite sides equal?

      ---

   8. In which groups is at least one pair of adjacent sides equal?

      ---

   9. In which groups is at least one pair of opposite sides parallel?

      ---

   10. In which groups are all the angles right angles?

       ---

2. The figures in group 1 are called parallelograms.

   1. What do you observe about the opposite sides of parallelograms?

      ---

   2. What do you observe about the angles of parallelograms?

      ---

3. The figures in group 2 are called kites.

   1. What do you observe about the sides of kites?

      ---

   2. What else do you observe about the kites?

      ---

   Group 1

   

   Group 2

   

   Group 3

   

   Group 4

   

   Group 5

   

   Group 6

   

4. The figures in group 3 are called rhombi.

   1. What do you observe about the sides of rhombi?

      ---

   2. What else do you observe about the rhombi?

      ---

   Note: One rhombus; two or more rhombi.

5. The figures in group 4 are called rectangles.

   1. What do you observe about the opposite sides of rectangles?

      ---

   2. What do you observe about the angles of rectangles?

      ---

   3. What do you observe about the adjacent sides of rectangles?

      ---

6. The figures in group 5 are called trapeziums. What do you observe about the opposite sides of trapeziums?

   ---

   The arrows show which sides are parallel to each other.

7. The figures in group 6 are called squares.

   1. What do you observe about the sides of squares?

      ---

   2. What do you observe about the angles of squares?

      ---

Comparing and describing shapes

1. Name each shape in each group.

   Group A

   ---

   

   ---

   

   ---

   

   Group B

   ---

   

   ---

   

   ---

   

2. In what way(s) are the figures in each group the same?

   Group A:

   ---

   Group B:

   ---

3. In what way(s) does one of the figures in each group differ from the other two figures in the group?

   Group A:

   ---

   Group B:

   ---

Finding unknown sides in quadrilaterals

Use what you know about the sides and angles of quadrilaterals to answer the following questions. Give reasons for your answers.

1. 

   1. What type of quadrilateral is ABCD?

      ---

   2. Name a side equal to AB.

      ---

   3. What is the length of BC?

      ---

2. 

   1. What type of quadrilateral is EFGH?

      ---

   2. What are the lengths of the following sides?

      EF:

      ---

      GH:

      ---

3. 

   1. What type of quadrilateral is JKLM?

      ---

   2. What is the length of JK?

      ---

4. 

   Figure PQRS is a kite with PQ = 4 cm and QR = 10 cm. Complete the following drawing by:

   1. labelling the vertices of the kite

   2. showing on the drawing which sides are equal

   3. labelling the length of each side.

Circles

1. 

   1. Make a dot in the middle of the circle on the right. Write the letter M next to the dot. If your dot is in the middle of the circle, it is called the midpoint or centre.

   2. Draw lines MA, MB and MC from M to the red points A, B and C.

   The three red points are on the circle with midpoint M.

   A straight line ,such as AC, drawn across a circle and passing through its midpoint is called the diameter of the circle.

2. Measure MA, MB and MC.

   ---

   If MA, MB and MC are equal in length, you have chosen the midpoint well.If they are not equal, you may wish to improve your sketch of a circle and its parts.

Similar and congruent shapes

Three groups of quadrilaterals are shown on this page and the next.

What makes each group different from the other groups, apart from the colours?

1. Group A:

   ---

2. Group B:

   ---

3. Group C:

   ---

   Group A

   

   Group B

   

   Group C

   

   Shapes that have the same form, such as the blue shapes on the previous page, are said to be similar to each other. Similar shapes may differ in size, but will always have the same shape.

   

   Example of similar shapes

   

   Example of congruent shapes

   Shapes that have the same form and the same size, such as the red shapes on the previous page, are said to be congruent to each other. These shapes are always the same size and shape.

4. Are the red shapes on the previous page similar to each other?

   ---

5. Look at groups D, E, F, and G on this page and the next. In each case say whether the shapes are similar and congruent, similar but not congruent, or neither similar nor congruent.

   1. Group D:

      ---

   2. Group E:

      ---

   3. Group F:

      ---

   4. Group G:

      ---

   Group D

   

   Group E

   

   Group F

   

   Group G

   

Term revision and assessment

Revision

You should not use a calculator for any of the questions in this section. Do show your steps of working.

Working with whole numbers

1. Make the number sentences below true. Into the first block in each question, write a multiplication or division sign. Into the second block, write either 10, 100 or 1 000.

   1. 8 ☐ ☐ = 800

   2. 740 000 ☐ ☐= 740

2. Circle all the numbers given below that will round off to 60 000.

   62 495; 54 498 ; 65 000; 56 002 ; 67 024

3. Calculate the following:

   1. \(274 561 + 367 238\)

      ---

   2. \(4 672 - 3 937\)

      ---

   3. \(3 458 \times 43\)

      ---

   4. \(6 624 \div 18\)

      ---

4. Write the missing numbers in the blocks.

   1. 8; 15; 22; 29; ☐

   2. 

5. Tumi makes a sequence of numbers using the following rule: "Take half the previous number and then add 12." Write the next three numbers in the sequence:

   56; 40; 32;

   ---

6. Two three-digit numbers are added together as shown, and produce a three-digit answer - but some of the digits are missing. Fill in the missing digits so as to make the calculation correct.

   59 ☐+ 3 ☐9=☐53

7. Ismail has the following numbers:

   71; 72; 73; 74; 75; 76; 77; 78; 79; 80

   He wishes to sort them by placing them in the sorting diagram below. Help Ismail by placing the numbers in the correct blocks.

   	Prime number	Not a prime number
   Multiple of 4
   Not a multiple of 4

8. Write down, using only numbers from the cloud:

   

   1. All the prime numbers

      ---

   2. All the square numbers

      ---

   3. All the cube numbers

      ---

   4. All the multiples of 8

      ---

   5. All the factors of 8

      ---

9. Teacher Ramushwana states:

   "Every even number (greater than or equal to 6) can be written as the sum of a

   pair of odd prime numbers, for example \(10 = 3 + 7\)."

   1. Write down two pairs of odd prime numbers that each sum to 20.

      ---

   2. Choose any even number greater than 30 and write it as a sum of two odd prime numbers.

      ---

10. 1. Write the following as a product of prime factors:

       1. 576

          ---

       2. 600

          ---

    2. Find both the (i) HCF and (ii) LCM of 576 and 600.

       1. HCF

          ---

       2. LCM (leave your answer as a product of prime factors)

          ---

11. How many hours will it take the Adams family to reach their holiday destination if it is 495 km away and they travel at an average speed of 110 km/h?

    ---

12. Graeme, Thuli and Andile have worked as a team over the holidays, mowing the lawns of their neighbours. They collected a total of R1 200 and now need to share it. They agree that as they didn't all work an equal amount, the money should be shared between Graeme, Thuli and Andile in the ratio 4 : 6 : 5. How much money will Thuli receive?

    ---

13. Mr Khumalo decides to try to make some money buying and selling used furniture. He has R6 000 in his bank account, and uses some of the money to buy an old bed base and mattress for R800, a dresser for R2 500, two lockers for R300 each, and a washing machine for R900.

    1. How much is left in his bank account after these purchases?

       ---

    2. Suppose that he sells the bed base and mattress for R980, the dresser for R2 950, and both lockers for a total of R750. Nobody seems to want his washing machine though. At this stage he has made a loss. What is the value of the loss?

       ---

    3. How much does he need to sell the washing machine for to have an overall profit of R1 000?

       ---

14. Mrs Steyn takes out a loan of R55 000 from Fidelity Bank. The bank charges simple interest of R500 per month. How much money will Mrs Steyn owe after \(1\frac{1}{2}\) years?

    ---

15. John earns R480 on a Saturday. He works from 08:00 to 14:00. Calculate his hourly rate.

    ---

Exponents

1. Calculate.

   1. \(12 \times 12\)

      ---

   2. \( 8 \times 8 \)

      ---

   3. \( 7 \times 7 \times 7\)

      ---

   4. \( 3 \times 3 \times 3 \)

      ---

   5. \( 6 \times 6 \times 6 \)

      ---

   6. \( 13 \times 13 \)

      ---

2. Explain the difference between \(4 \times 3\) and \(4^3\).

   ---

3. Write \( 5^5\) in expanded form.

   ---

4. Write the following in exponential form:

   1. \( 2 \times 2 \times 2 \)

      ---

   2. \( 3 \times 3 \times 3 \times 3 \times 3 \times 3 \times 3 \times 3 \)

      ---

5. Write the numbers in exponential form. Check your answers.

   1. 81

      ---

   2. 10 000

      ---

6. Complete:

   1. 5 squared is

      ---

   2. 5 cubed is

      ---

7. Calculate:

   1. \( 7^2\)

      ---

   2. \( 15^2\)

      ---

   3. \(3^2 \times 4^2 \)

      ---

   4. \(\sqrt{16}\)

8. Are the following statements true or false? Explain your answers.

   1. The number 64 can be written both as a square and a cube.

      ---

   2. \( 2^5\) is smaller than \(30^1\).

      ---

9. Calculate the following and give reasons for your answers.

   1. \(\sqrt[3]{216}\)

      ---

   2. \(\sqrt[3]{8}\)

      ---

   3. \(\sqrt[3]{125}\)

      ---

   4. \(\sqrt[3]{27}\)

      ---

10. Determine the value of each of the following:

    1. \( 3^2-2^3\)

       ---

    2. \(4(10 - 1^{100})\)

       ---

    3. \((8-2)^2\)

       ---

    4. \(\sqrt{4} \times \sqrt{81}\)

       ---

    5. \((\sqrt{58})^2\)

       ---

    6. \(\sqrt[3]{27} \div \sqrt{9}\)

       ---

    7. \(10 \times \sqrt{81}\)

       ---

    8. \(\sqrt{2 \times 32}\)

       ---

11. \(13=169; 14^2 =196; 15^2=225; 16^2=256; 7^3=343; 8^3=512; 3^3=27\)

    Use these facts to calculate the value of each of the following:

    1. \(\sqrt{196}-\sqrt[3]{512}\)

       ---

    2. \(\sqrt{169 \times 225}\)

       ---

    3. \(\frac{\sqrt{196}}{\sqrt[3]{343}}\)

       ---

    4. \(\frac{14^2- 13^2}{3^3}\)

       ---

12. If \(56^3= 175 616\), write down the value of \(\sqrt[3]{175 616}\).

    ---

Geometry of straight lines

1. Consider the grid shown alongside.

   1. Is PS a line, ray or line segment?

      

      ---

   2. Draw on the grid a line segment through R that will be perpendicular to PS. Label it TU.

   3. Draw on the grid a line that is parallel to PS. Label it WX.

2. Provide the correct name for each of the geometric features AB and CD, shown on the diagram:

   

   AB:

   ---

   CD:

   ---

3. There is a geometric relationship between line segments PR and QS shown in the diagram. Describe the relationship by adding the correct word on the dotted line:

   

   PR is ____________ QS.

4. Draw a ray and a line that will never meet.

Construction of geometric figures

1. Use a protractor to accurately measure the following angles, as shown on the diagram below, and write the answers in the table provided:

   1. \(\hat{B}\)

   2. \(A\hat{D}B\)

      ---

   3. \(D\hat{A}B\)

      ---

   4. \(C\hat{D}B\)

      ---

   5. reflex \(C\hat{A}B\)

      ---

   

   Angle name	Size	Classification
   \(\hat{B}\)
   \(A\hat{D}B\)
   \(D\hat{A}B\)
   \(C\hat{D}B\)
   Reflex \(C\hat{A}B\)		Reflex

2. Construct a semi-circle with a radius of 3 cm.

   

3. Use a ruler and protractor to construct angles that are the given sizes. Label the angles correctly.

   1. \(E\hat{F}G = 152^{\circ}\)

   2. \(X\hat{Y}Z = 289^{\circ}\)

   

4. Use circles to construct two lines, CD and EF, that are parallel to line AB below. Line CD should be above line AB, and line EF below line AB. Label both lines.

   

5. Consider the diagram alongside.Write down the names of the pair of perpendicular lines.

   

   ---

Geometry of shapes

1. Give the full name of the shape that fits the given descriptions:

   1. A three-sided shape that has exactly two sides equal in length

      ---

   2. A four-sided shape with both pairs of opposite sides parallel and equal in length, and with no right angles

      ---

   3. A four-sided shape with only one pair of opposite sides parallel

      ---

2. What is the correct term for each of the following parts of the circle with centre B, as shown alongside?

   

   1. Line AB

      ---

   2. The shaded area

      ---

3. On the square grid alongside, two sides of a kite have been drawn. Use a ruler and complete the kite on the grid.

   

4. Darrel says, "The four-sided shapes I am thinking of have at least one pair of adjacent sides equal. What are they?" Write down the names of all the shapes that fit his description.

   ---

5. DEFG is a kite, and DE = 4 cm and EF = 5,2 cm. Write down the lengths of DG and GF.

   ---

6. STUV is a rectangle. Write down the value of \(\hat{T} + \hat{V}\). Give a reason for your answer.

   ---

7. Consider the diagram alongside.

   

   1. Write down the letters of all the shape(s) that are congruent to shape B.

      ---

   2. Write down the letters of all the shape(s) that are similar to shape B.

      ---

8. An isosceles triangle, LMN, has LM = 4 cm and a perimeter of 16 cm. Investigate and write down all the possible lengths of MN and LN.

   ---

9. In each case say whether the two sides are opposite sides or adjacent sides of quadrilateral DEFG.

   

   1. GD and DE

      ---

   2. DE and GF

      ---

Assessment

In this section, the numbers indicated in brackets at the end of a question indicate the number of marks that this question is worth. Use this information to help you determine how much working is needed.

The total number of marks allocated to the assessment is 60.

1. Here are five one-digit cards:

   

   Two-digit numbers can be made by placing two cards next to each other - so, for example, taking the 1 and the 2 and putting them next to each other will create the number 12 (twelve).

   Choose two cards each time to make the following two-digit numbers:

   1. An odd number

      ---

   2. A multiple of 9

      ---

   3. A factor of 126

      ---

   4. A square number

      ---

2. Ayanda has a pack of cards numbered from 1 to 16. He chooses four cards at random from the pack:

   • One is a factor of 39.
   • Two are multiples of 4.
   • Three are even.
   • The total of the four numbers is more than 45, but less than 50.

   Write down the values of the four numbers.

   ---

3. All 769 learners from the Sibanye Primary School are going to an athletics meeting. The school hires buses from a local company. Each bus can take only 52 passengers, and each bus has to have two teachers on board. How many buses will the school have to hire to get everyone to the meeting?

   ---

4. Calculate the total number of test wickets taken by the top four wicket takers in the Proteas' cricket history (figures correct as at June 2013):

   • Shaun Pollock: 421
   • Makhaya Ntini: 390
   • Dale Steyn: 332
   • Allan Donald: 330

   ---

5. Use prime factors to find the LCM of 42 and 18.

   ---

6. Dintle's family needs to get to Polokwane, 330 km away, by 11 a.m. If they leave at 7.40 a.m. and drive at an average speed of 100 km/h, will they reach their destination on time? Show all your working.

   ---

7. Determine the value of each of the following:

   1. \( 6^3 - (7^2 + 6^2)\)

      ---

   2. \((8-5)^3\)

      ---

   3. \((\sqrt[3]{125})^2\)

      ---

   4. \(12^2 - 4\sqrt{121} \div 2^2\)

      ---

   5. \(3\sqrt{64}\)

      ---

8. 1. Write down the letters of all the acute angles in the diagram.

      ---

      

   2. Measure the size of angle \(d\) in the diagram and write it down.

      ---

   3. Classify angle \(d\) according to its size.

      ---

9. Draw and correctly label angle \(K\hat{L}M = 168^{\circ}\).

   

10. Use your ruler and protractor to draw a line that is parallel to line segment FG drawn below, and goes through point H.

    

11. Four circles are drawn so that they fit neatly into a square with side length of 6 cm, as shown (not to scale). Write down the radius of each circle.

    

    ---

12. 1. What is the geometrical name of the shape shown on the dot grid below?

       ---

    2. Draw two shapes that are similar to the shape shown, anywhere on the grid. Each shape that you draw should have a different size.

    

13. The following diagram shows a square drawn on a dot grid. The square is divided into four triangles, namely A, B, C, and D.

    

    1. Write down the letters of all the right-angled triangles.

       ---

    2. Write down the letters of all the isosceles triangles.

       ---

    3. Write down the letters of the two congruent triangles.

       ---

14. I am a quadrilateral with two pairs of opposite sides equal, no adjacent sides equal, and no right angles. What shape am I?

    ---

15. What is the special name we give to the perimeter of a circle?

    ---

16. Draw a rhombus of any size on the dot grid below. Add appropriate symbols on the diagram to show that the opposite sides of a rhombus are parallel.

    

17. In trapezium JKLM, JK is parallel to the opposite side.

    Complete the statement:

    JK ||

    ---

18. Study the following diagram:

    

    Cross out the incorrect word or symbol in each set of brackets:

    AD is (parallel/perpendicular) to BC. This can be shown in symbols as follows:

    (AD \(\perp\) BC / AB || BC).