A cylinder has a circular face with a diameter of 10cm, and a body of length 30cm. Calculate the volume of the cylinder.

First recognise that the diameter is 10cm so the radius of the circle must be 5cm.

Next use the formula for the area of a circle, πr², to work out the area of the circular face:

Area = 25πcm²

Multiply this area by the length of the cylinder to find the volume:

Volume = 25πcm² x 30cm = 750πcm³