A cylinder can be considered as lots of circular discs stacked one above the other.
If the area of each circular disc is A and the height of the stack is h, then the volume = Ah.
Remember that the area of a circle with radius r = πr2
We can write this instead of A, so the volume of a cylinder with radius r and height h = πr2h
Find the volume of this cylinder in cm3 to 3 significant figures.
Diameter = 6 cm
Radius = 6 ÷ 2 = 3 cm
Height = 12 cm
Volume = πr2h = π × 32 × 12 = 339.29 ≈ 339 cm3 (3 s.f.)