Volume of a prism
A prism has a uniform cross-section of area and a length of .
(a) Calculate its volume. (b) Explain why the same formula works whatever the shape of the cross-section.
- 1
(a) A prism's volume is its cross-sectional area times its length.
- 2
(b) The cross-section is the same all the way along, so the solid is that shape repeated — the shape itself does not matter.
Answer
(a) (b) the cross-section is uniform, so volume is area × length whatever its shape
Examiner tip
A cylinder is just a prism with a circular cross-section, which is why is the same rule. Use the length perpendicular to the cross-section, not a slanted edge.