Class 9 Maths — Surface area and volume
Find surface areas and volumes of cones, spheres and hemispheres.
Name: ________________________
1.Which of these gives the volume of a sphere?
- a) (4/3) × π × r × r × r
- b) 4 × π × r × r
- c) 2 × π × r × r
- d) (1/3) × π × r × r × h
2.A sphere has a radius of 14 cm. Take π = 22/7. What is its surface area, in square centimetres?
3.A cone has a radius of 7 cm and a height of 24 cm. What is its slant height, in centimetres?
4.Match each solid to the formula for its volume.
- Cuboid
- Cylinder
- Cone
- Sphere
- length × width × height
- (4/3) × π × r × r × r
- π × r × r × h
- (1/3) × π × r × r × h
5.A cone has a radius of 7 cm and a slant height of 25 cm. Take π = 22/7. What is its curved surface area, in square centimetres?
6.A sphere has a radius of 7 cm. Take π = 22/7. What is its surface area, in square centimetres?
7.A cone has a radius of 7 cm and a height of 12 cm. Take π = 22/7. What is its volume, in cubic centimetres?
8.A hemisphere has a radius of 7 cm. Take π = 22/7. What is its total surface area, in square centimetres?
Answer key — Class 9 Maths — Surface area and volume
- 1. a) (4/3) × π × r × r × r
- 2. 2464
- 3. 25
- 4. Cuboid → length × width × height; Cylinder → π × r × r × h; Cone → (1/3) × π × r × r × h; Sphere → (4/3) × π × r × r × r
- 5. 550
- 6. 616
- 7. 616
- 8. 462