103：
Complete the table below. (Take π = 3.14 and give your answers correct
to two decimal places.)
Circle
Radius
Diameter
Circumference
(a)
A
6 cm
(b)
(c)
(d)
(e)
(f)
B
C
D
E
F
0.4 cm
1.9 cm
0.9 cm
37.68 m
31.4 m
107：
Solve the problem.
The diameter of a circular coin is 2.4 cm. Find its circumference.
(Take π = 3.14 and give your answer correct to two decimal places.)
108：
Solve the problem.
The diameter of a circular fountain is 4
1
5
(Take π =
22
7
.)
m. Find its circumference.
109：
Solve the problem.
The radius of the bottom of a circular glass is 2
4
cm. Find its
5
circumference. (Take π =
22
.)
7
110：
Solve the problem.
The diameter of a circular table is 0.95 m. Find its circumference.
(Take π = 3.14 and give your answer correct to two decimal places.)
111：
Solve the problem.
A clown is cycling along a steel wire on his mono-bike. The diameter of
the wheel is 40 cm. What is its circumference? (Take π = 3.14.)
112：
Solve the problem.
There is a circular clock. The length of its minute hand is 40 cm. How
many centimeters has the tip of the minute hand run after going around
once? (Take π = 3.14.)
113：
Solve the problem.
The diameter of a radar screen is 30 cm. What is its circumference? (Take
π = 3.14.)
114：
Solve the problems. (Take π = 3.14 and give your answers correct to two
decimal places if necessary.)
The figure shows two circular cardboards is overlapped at the same
centre.
(a) What is the circumference of the large cardboard?
(b) What is the circumference of the small cardboard?
115：
Solve the problem.
The diameter of a circular swimming pool is 7 m. There is a path of width
0.7 m around the pool. What is the circumference of the outer edge of the
path? (Take π =
22
.)
7
116；
Solve the problem.
The circumference of a circular button is 4.4 cm. What is its diameter?
(Take π =
22
7
117：
.)
Solve the problem.
The circumference of a circular button is 3.77 cm. What is its diameter?
(Take π = 3.14 and give your answers correct to 1 decimal place.)
118：
Solve the problem.
The circumference of a circular watch face is 15.7 cm. What is its
diameter and its radius? (Take π = 3.14.)
119：
Solve the problem.
The circumference of a circular flower bed is 18.84 m. What is the
diameter and the radius of the flower bed? (Take π = 3.14.)
120：
Solve the problem.
To wrap round a pillar 3 times, 4.5 m of string has to be used. What is the
diameter of the pillar? (Take π = 3.14 and give your answer correct to one
decimal place.)
121：
Solve the problem.
The diameter of the wheel of a locomotive is 1.5 m. After rotating 300
times, how many metres has the locomotive travelled? (Take π = 3.14.)
122：
Solve the problem.
The diameter of the wheel of a bicycle is 70 cm. how many rounds has
the wheel rotated after travelling a distance of 660 m? (Take π =
22
.)
7
123：
Solve the problem.
The radius of a bicycle wheel is 33 cm. The radius of a monocycle wheel
is 20 cm. What is the difference between the circumferences of the two
wheels? (Take π = 3.14.)
124：
Solve the problem.
The diameter of the wheel of a big lorry is 1.35 m. How many metres has
the wheel moved after rotating 100 times? (Take π = 3.14.)
125：
Solve the problem.
The radius of the wheel of a performing monocycle is 20 cm. How many
metres has the wheel moved after rotating 10 times? (Take π = 3.14.)
126：
Solve the problem.
The diameter of a cylindrical bucket is 30 cm. How many metres of iron
wire are needed to mount its circular surface two rounds? (Take π = 3.14.)
127：
Solve the problem.
The sport ground below is formed with a square and two semi-circles.
There is a running track of 8 m wide around the sport ground. If an iron
rail is to be mounted around the outside of the track, how long is the rail?
(Take π = 3.14.)
304:
Complete the table below. (Take π =
22
.)
7
Circle
Diameter (cm)
(a)
A
3
(b)
B
4
(c)
C
5
305:
Circumference (cm)
Complete the table below. (Take π =
22
.)
7
Circle
Diameter (cm)
Circumference (cm)
2
(a)
D
1
5
4
(b)
E
2
5
2
(c)
F
3
11
1
(d)
G
4
2
306:
In the circle below, ‘×’ is the centre. Find the diameter and the
circumference of the circle. (Take π = 3.14.)
The diameter is
The circumference is
cm.
cm.
307:
In the circle below, ‘×’ is the centre. Find the diameter and the
circumference of the circle. (Take π = 3.14.)
The diameter is
The circumference is
cm.
cm.
308:
In the circle below, ‘×’ is the centre. Find the diameter and the
circumference of the circle. (Take π = 3.14.)
The diameter is
The circumference is
cm.
cm.
309:
In the circle below, ‘×’ is the centre. Find the diameter and the
circumference of the circle. (Take π = 3.14.)
The diameter is
The circumference is
310:
cm.
cm.
Find the perimeter of the figure below. (Take π = 3.14.)
28 cm
The perimeter of the figure is
cm.
311:
Find the perimeter of the figure below. (Take π = 3.14.)
10 cm
10 cm
10 cm
The perimeter of the figure is
cm.
312:
Find the perimeter of the figure below. (Take π = 3.14.)
3 cm
The perimeter of the figure is
3 cm
cm.
313:
Find the perimeter of the figure below. (Take π = 3.14.)
100 m
100 m
150 m
The perimeter of the figure is
cm.
314:
Find the perimeter of the figure below. (Take π =
22
7
.)
14 cm
The perimeter of the figure is
14 cm
cm.
315:
Find the perimeter of the figure below. (Take π =
22
7
26 cm
26 cm
.)
The perimeter of the figure is
cm.
316:
Solve the problem.
It is given that the circumference of a circle is 69
1
7
of the circle. (Take π =
22
.)
7
The radius of the circle is
cm.
cm. Find the radius
317:
Solve the problem.
A piece of string is 129 cm long. It can be used to wrap around a
cylindrical vase 3 times. What is the diameter of the base of the vase?
(Take π =
22
.)
7
The diameter of the base of the vase is
cm.
318:
Find the perimeter of the figure below. (Take π = 3.14.)
6 cm
4 cm
4 cm
8 cm
The perimeter of the figure is
cm.
319:
Solve the problems. (Take π = 3.14.)
Father bought two video discs of different sizes.
12 cm
30 cm
Disc A
Disc B
(a) What is the outer circumference of disc A?
The outer circumference of disc A is
(b) What is the outer circumference of disc B?
cm.
The outer circumference of disc B is
cm.
(c) What is the difference between their outer circumferences?
The difference between their outer circumferences is
cm.
320:
Solve the problem.
The length of each side of a piece of square craft paper is 20 cm. What is
the circumference of the largest possible circle is to be cut out from the
craft paper? (Take π = 3.14.)
How should
the circle be
cut out?
The circumference of the largest possible circle is
cm.
321:
Solve the problem.
The lengths of the hour hand and minute hand of a clock are 5 cm and 7
cm respectively. How many centimetres have the tips of the two hands
moved after 15 minutes respectively? (Take π =
22
.)
7
15 minutes =
hour
The tip of the minute hand has moved
The tip of the hour hand has moved
cm.
cm.
322:
Solve the problem.
The wheel of a bicycle has moved 315 m after rotating 180 times. What is
the diameter of the wheel of the bicycle? (Take π =
22
7
.)
The diameter of the wheel of the bicycle is
m.
323:
Solve the problem.
The diameter of the wheel of a bicycle is 63 cm. Joe ride it at a regular
speed of 18 m/s. How many rounds has the wheel rotated per second on
average? (Take π =
22
and give your answer correct to the nearest
7
whole number.)
The wheel is rotating at about
18 m = (18 × 100) cm
rounds per second on average.
446:
Below is a semi-circle. The dotted line can go through the centre.
(a) Complete the circle using a compass.
(b) Use a ruler to measure the diameter of the circle.
The diameter is
cm.
(c) The circumference of the circle is
cm. (Take π = 3.14.)
447:
Look at the picture and solve the problems. (Take π = 3.14.)
Mother bought a photo frame which can hold 2 round photos.
4 cm
4 cm
(a) How long is the circumference of each small circle?
The circumference of each small circle is
cm.
(b) How long is the circumference of the large circle?
The circumference of the large circle is
cm.
(c) Compare the circumference of the large circle and the sum of the
circumferences of the two small circles, which is longer?
448:
Find the perimeter of the figure below. (Take π = 3.14.)
4.5 cm
4.5 cm
The perimeter of the figure is
cm.
449:
Find the perimeter of the figure below. (Take π = 3.14.)
9 cm
9 cm
The perimeter of the figure is
cm.
450:
Find the perimeter of the shaded region in the figure below. (Take π =
3.14.)
7 cm
7 cm
The perimeter of the shaded region in the figure is
cm.
451:
Find the perimeter of the shaded region in the figure below. (Take π =
3.14.)
2 cm
2 cm
2 cm
2 cm
The perimeter of the shaded region in the figure is
cm.
452:
Find the perimeter of the shaded region in the figure below. (Take π =
3.14.)
5m
5m
5m
5m
The perimeter of the shaded region in the figure is
m.
453:
Find the perimeter of the figure below. (Take π = 3.14.)
3m
3m
3m
3m
3m
3m
3m
3m
The perimeter of the figure is
m.
455:
Solve the problem.
The flower in the picture is formed with six semi-circles of radius 3 cm.
What is the perimeter of the flower? (Take π = 3.14.)
The perimeter of the flower is
cm.
456:
Solve the problem.
The diameter of a cylindrical box is 9 cm. Each is wrapped up using a
ribbon as shown in the figure. If 30 cm of the ribbon is needed for making
the bow, how many boxes can be wrapped up with 400 cm of ribbon at
most? (Take π = 3.14.)
457:
Find the perimeter of the figure below. (Take π = 3.14.)
5 cm
The perimeter of the figure is
5 cm
cm.
458:
Find the perimeter of the figure below. (Take π = 3.14.)
8 cm
The perimeter of the figure is
8 cm
cm.
459:
Solve the problems.
The figure shows the part of the pedal and the gear of a bicycle. ‘×’ is the
centre of each gear. (Take π = 3.14.)
15 cm
C
10 cm
B
45 cm
A
(a) When the pedal goes one round, how many centimetres have point A
(the pedal part) and point B (the bigger gear) moved respectively?
Point A has moved
cm.
Point B has moved
cm.
(b) When the pedal goes one round, how many rounds has point C (the
small gear) rotated?
Point C has rotated
rounds.
460:
Solve the problem.
The diameter of a piece of round paper is 1 m. It is cut into three equal
parts. What is the total perimeter of these three parts? (Take π = 3.14.)
Think how to
cut the paper!