CHAPTER 10
Exercise 1
1.
Circle 1
Basic Circle Work
Use any suitable object to draw a circle.
Show two separate diameters and radii on your circle.
2.
Draw another circle with a diameter and a radius.
Label all parts of your diagram.
3.
Write the length of the diameter for a radius of length :a
4.
3 cm
b
7 cm
c
52 m
d
8·5 km.
d
6·5 km.
Write the length of the radius for a diameter length of :a
5.
12 cm
b
56 cm
c
1m
Eight CD’s each with a 6 cm
radius are placed end to end.
What is the total length ?
Exercise 2
1.
?
The Circumference (C) of a circle
Copy and complete,
“ The formula for finding the circumference of a circle is C = .........
2.
Find the circumference of each of the following circles :–
a
b
c
d
1 cm
10 cm
©TeeJay Publishers 2012 Book 3a
17 cm
5m
page 40
Ch 10 Circle 1
2.
e
f
30 cm
15 cm
3.
A satellite orbits 900 km above the earth.
Assuming the radius of the earth is
6350 km, calculate the distance the
satellite travels in one orbit.
Exercise 3
1.
Circle Problems
A metal strip is bent into a semi-circle
with diameter 40 cm.
Find the length of the metal strip.
2.
40 cm
A garden is in the shape of a semi-circle with diameter 10 m.
Calculate the perimeter of the garden.
10 m
3.
A kitchen tile has a quarter circle shape.
The tile has a 24 cm radius.
24 cm
Calculate the perimeter of the tile.
4.
A garden path has a fence made from metal poles bent into semi-circles.
Each semi-circle has a radius of 20 cm.
20 cm
a
Find the length of pole needed to make a fence 10 metres long.
b
It costs £4·75 per metre for the metal pole.
If you must buy whole metre length only, how much will the fence cost ?
©TeeJay Publishers 2012 Book 3a
page 41
Ch 10 Circle 1
5.
Calculate the perimeter of each composite shape below :–
a
b
6 cm
20 cm
5 cm
Exercise 4
1.
Finding the Diameter of a Circle
Find the diameter of a circle
with circumference 125·6 cm.
Copy and complete :–
D = D = C
C = 125·6 cm
π
125·6
3·14
D = ....
2.
Calculate the diameter of each circle below :–
a
b
C = 25·12 cm
c
d
C = 47·1 cm
C = 376·8 m
C = 17·27 cm
3.
Find the radius of a circle with circumference 81·64 mm.
4.
Three circles overlap at their centres as shown.
Each circle has a circumference of 78·5 cm.
Find the total length of the diagram.
©TeeJay Publishers 2012 Book 3a
length
•
page 42
•
•
Ch 10 Circle 1
Revisit - Review - Revise Exercise 10
1.
Calculate the circumference of each of these :–
a
b
1260 mm
86 cm
2.
A semi-circular console table has
a diameter of 1·2 metres.
Calculate the perimeter of the table top.
3.
4.
Calculate the radius of a circular garden
which has a circumference of 172·7 metres.
Calculate the perimeter of each shape below :–
a
b
12 cm
8 cm
25 cm
A fence is built from metal rods
using quarter circles.
a
Find the length of one of
the quarter circles.
b
Find the total length of metal
needed to build the fence.
c
At £6·50 per metre, find the
total cost of the fence.
(Only sold in whole metre lengths).
©TeeJay Publishers 2012 Book 3a
80 cm
5.
20 cm
page 43
Ch 10 Circle 1