The volume of a cylinder is the area of the circular end face multiplied by the height (or length).

The formula is V = πr²h

where r is the radius of the circle, and h is height (or length).

This metal rod has a diameter of 20 mm and a length of 200 mm. What is the volume of metal in the rod?

r = 10 mm (half the diameter), h = 200 mm. Substitute in the formula:

V = 3.14 × 10 × 10 × 200

= 314 × 200

= 62 800 mm³