The formula for the volume of a cone, V, in terms of its base radius, r, is:
This is similar to the formula for the volume of a cylinder, but remember to divide by 3.
Example
Calculate the volume of the cone shown below in cm3 to 3 significant figures.
Answer
Diameter d = 8 cm
Radius r = 8 ÷ 2 = 4 cm
Height h = 10 cm
Volume = 1/3πr2h = π x 42 x 10 ÷ 3 = 167.55.... ≈ 168 cm3 (3 s.f.)