Circles, Cylinders, Cones and Spheres Exercise

Use pi, π = 3.1 for all of the questions in this exercise.

1. For the circle shown below, where O is the centre, name:

a. Three radii
b. A diameter

Y7_Circles_Cylinders_Cones_and_Spheres_ex_01.gif

2. What is the diameter of the following circles?

 

a.

Y7_Circles_Cylinders_Cones_and_Spheres_ex_02.gif

b.

Y7_Circles_Cylinders_Cones_and_Spheres_ex_03.gif

3. What is the radius of the following circles?

a.

Y7_Circles_Cylinders_Cones_and_Spheres_ex_04.gif

b.

Y7_Circles_Cylinders_Cones_and_Spheres_ex_05.gif

4. Complete the table below for these common circular objects (measured to 1 decimal place) :

 
Object
Circumference
Diameter
Circumference ÷ diameter
a Soccer ball
21.4 cm
6.8 cm
 
b Can lid
6.2 cm
2 cm
 
c Two dollar coin
24 mm
7.7 mm
 
d Mars
21310 km
6790 km
 
e Clock
54.7 cm
17.4 cm
 

What name is given to this ratio?

5. Find the circumferences and areas of the following circles.

a
b
Y7_Circles_Cylinders_Cones_and_Spheres_ex_06.gif
Y7_Circles_Cylinders_Cones_and_Spheres_ex_07.gif

6.

a. The radius of a circular desk is 1.3 metres, what is its diameter?
b. Find the area of a circle with a diameter of 10 centimetres.
c. What is the radius of a circle with a circumference of 34.2 cm?
d. What is the diameter of a circle with an area of 49.6 cm2?

7. Find the area that is shaded red.

Y7_Circles_Cylinders_Cones_and_Spheres_ex_08.gif

8. Find the volumes of the following solids:

a. A cylinder with a circular base of radius 5 centimetres and a height of 10 centimetres.
b. A sphere with a radius of 6 centimetres.
c. A cone with a base of 5 cm and a height of 10 cm.