# 4.03 Circumference of circles and sectors

Worksheet
Circumference
1

Find the circumference of the following circles, rounding your answers to two decimal places:

a
b
c
d
e
f
2

Find the circumference of the following circles, rounding your answers to two decimal places:

a

A circle with a radius of 7\text{ cm}.

b

A circle with a radius of 11\text{ cm}.

c

A circle with a radius of 27\text{ cm}.

d

A circle with a radius of 1.8\text{ cm}.

e

A circle with a diameter of 38\text{ cm}.

3

Find the radius r of the circle shown with circumference of 44\text{ cm}. Round your answer to two decimal places.

4

Find the diameter D of the circle shown with circumference of 42\text{ m}. Round your answer to two decimal places.

5

Find the radius of the following circles, correct to two decimal places.

a

A circle with circumference 14\text{ cm}.

b

A circle with circumference 18\text{ m}.

c

A circle with circumference 98\text{ m}.

d

A circle with circumference 14.9\text{ m}.

6

Find the diameter of the following circles, correct to two decimal places.

a

A circle with circumference 44\text{ m}.

b

A circle with circumference 70\text{ m}.

c

A circle with circumference 24.5\text{ cm}.

Sectors
7

For each of the following sectors, find the length of the arc to one decimal place:

a
b
c
d
e
8

Find the perimeter of the following semicircles given their radii. Round your answer to two decimal places.

a

r = 2\text{ cm}

b

r = 19\text{ cm}

9

Find the perimeter of the following semicircles given their diameters. Round your answer to two decimal places.

a

D = 17.23\text{ cm}

b

D = 8\text{ cm}

10

Find the perimeter of the following sectors. Round your answer to two decimal places.

a

A sector equal to one quarter of a circle with radius 5\text{ cm}.

b

A sector equal to one quarter of a circle with radius 17\text{ cm}.

c

A sector equal to three quarters of a circle with radius 9.86\text{ cm}.

d

A sector equal to three quarters of a circle with radius 42\text{ cm}.

e

A sector equal to one third of a circle with radius 9\text{ cm}.

f

A sector equal to one third of a circle with radius 2.74\text{ cm}.

g

A sector equal to two thirds of a circle with radius 19\text{ cm}.

11

Find the perimeter of the following shapes. Round your answers to two decimal places:

a
b
c
d
e
Applications
12

The bottom of a flower pot has a radius of 16\text{ cm}. What is the circumference of the bottom of the flower pot? Round your answer to one decimal place.

13

A scooter tyre has a diameter of 34\text{ cm}. What is the circumference of the tyre? Round your answer to one decimal place.

14

A coin has a diameter of 2.2\text{ cm}. If the coin is rolled through 45 complete revolutions, what distance will it travel? Round your answer to one decimal place.

15

A circular running track has a diameter of 23 metres. How many laps must be completed to run 1600 metres? Round your answer to one decimal place.

16

The wheel of Roxanne's bicycle has a radius of 22\text{ cm}. How far would she cycle if the wheels made 250 complete revolutions? Give your answer in metres, correct to one decimal place.

17

Carl is performing an experiment by spinning a metal wheel around on the end of a nylon thread. How far does the metal wheel travel if it completes 40 revolutions on the end of a 0.65\text{ m} thread? Round your answer to one decimal place.

18

The diameter of the front wheel of a car is 0.4\text{ m}. How many complete revolutions will the wheel make if the car travels a distance of 50\text{ km}?

19

A record has a diameter of 30\text{ cm} and is played at a speed of 33\dfrac{1}{3} revolutions per minute. Through what total distance will a point on the rim of the record travel if the record takes 28 minutes to play? Give your answer in metres, correct to one decimal place.

20

A shallow circular wading pool has a diameter of 4 metres. A deeper circular swimming pool has a radius of 16 metres. How many times greater is the circumference of the swimming pool than the wading pool?

21

What is the length of the strip of seaweed around the outside of the given sushi? Round your answer to one decimal place.

22

What is the circumference of the Ferris wheel? Round your answer to one decimal place.

23

A satellite is orbiting the Earth at a height of h\text{ km} above the Earth's surface. In one complete orbit, the satellite travels a distance of 41\,664 \text{ km}. If the radius of the Earth is 6400 \text{ km}, find the height of the satellite above the Earth.