Question

A right circular cylinder has a diameter of 16 mm and a height of 12 mm. what is the volume of the cylinder in terms of π?

Answer 1

Volume of the cylinder = hr²π

diameter = 2 × radius
16 = 2 × r
r = 16/2
r = 8 mm

V = hr²π
V = 12 × 8² × π
V = 12 × 64 × π
V = 768π  mm³

Answer 2

V = π·r²·h 
and D = 2·r => r = 16 : 2 = 8 mm

V = π·8²·12 = π·64·12 = 768 π mm³