49 Penerbitan Pelangi Sdn. Bhd.

CHAPTER

1. By using the letters given in the diagram, complete the given table.

O

C

D

B

E

A

Part of circle Example(s)

(a) Radius

(b) Diameter

(c) Chord

(d) Semicircle

(e) Minor arc

(f) Major arc

(g) Minor sector

(h) Major sector

(i) Segment

2. By using a pair of compasses and a ruler, draw the following parts of a circle.

(a) A circle with centre P and a radius of 1.5 cm.

P

(b) (i) A circle with TU as its radius and T as the centre. (ii) A chord UR of 2 cm.

U

T

CHAPTER

Circles10

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3. By construction, show the centre O of the circle below. Hence, measure the length of the radius.

4. Calculate the circumference of a circle with diameter 2.1 m. 1Use = 227 2

5. Calculate the circumference of a circle with radius 2.8 m. 1Use = 227 2

6. Find the diameter of circle with circumference 37.5 m. (Use = 3.14)

7. Find the radius of a circle with circumference 63.5 mm. (Use = 3.14)

8. Solve each of the following problems.

(a) A round-shape cake has a circumference of 54 cm. What is the radius of the cake? (Use = 3.142)

(b)

A ball fits exactly into a square box as shown in the diagram. If the length of the box

is 21 cm, find the circumference of the circle. 1Use = 227 2

9. Calculate the arc length of the following sector. 1Use = 227 2

754.2 cm

O

10. Find the angle subtended at the centre of the following sector. 1Use = 227 2

O

P

Q

21 cm

Arc length= 29.33 cm

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11. Calculate the radius of the following sector. 1Use = 227 2

O

P Q

56

28 cm

12.A

ED

B C

378 cm

4 cm

6 cm

In the diagram, ABC is a right-angled triangle with AB = 8 cm and BC = 6 cm. ADE is a sector with centre A and DAE = 37. Find the perimeter of the shaded region. (Use = 3.142)

13. Calculate the area of the circle below. (Use = 3.14)

O

Diameter= 15 cm

14. Calculate the radius and the diameter of a circle with area 202.25 cm2. (Use = 3.142)

15. Calculate the radius and the area of a circle with circumference 24.43 cm. (Use = 3.142)

16. Calculate the radius and the circumference of a circle with area 3160 cm2.

1Use = 227 2

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17.

AB

C

The diagram shows two semicircles with diameter AB and BC respectively. Given that

AB = 2r cm and BC = 3r cm. If the area of the shaded region is 40 58 cm2, calculate the

value of r.

18. Calculate the area of the sector below. (Use = 3.142)

O

A

B

165

4.5 cm

19. Calculate the angle subtended at the centre of a sector with area 13.86 m2 and radius 5.4 m. (Use = 3.14)

20. Calculate the radius of a sector with area 1.9625 cm2 and angle subtended at the centre is 36. (Use = 3.14)

21. 2r cm

B

O r cm C

A

The diagram above shows a trapezium OABC and a quadrant OAC. Given that OC = r cm and AB = 2r cm and the area of the shaded region is 5.6 cm2, calculate the value of r.

1Use = 227 2