Volumes of Circle Shapes

Volumes of Circle Shapes

GCSE(F), GCSE(H),

The volume of a cone is given by Volume = `frac(1)(3)` x base area x vertical height, or `frac(1)(3)`Ah

The base area is that of a circle, πr2

The volume of a sphere is given by Volume = `frac(4)(3)`πr3

Examples

1. A solid wooden cone has a vertical height of 24 cm and a diameter across its base of 6cm. What is the volume of the cone?

Answer: 56.52 cm3

The area of the base = `πr^2`

`A = π (frac(3)(2))^2` (divide diameter by 2 for the radius)

`A = 7.065`

Volume of cone = `frac(1)(3)Ah`

`V = 56.52`

2. A globe has a radius of 15cm. What is the volume of the globe?

Answer: 14 130 cm3

Volume of a globe = `frac(4)(3)πr^3`

`V = frac(4)(3) xx π xx 15^3`

`V = 14130` cm^3^