Geometry & measures · Perimeter, area & volume
Chapter 1 · 4
The idea
Volume of prisms, cylinders, cones & spheres
Why a prism's volume is cross-section × length, why a cylinder is just a circular prism, where the ⅓ in pyramid and cone formulas fits in, spheres and hemispheres, and litres.
A full journey — read it, play with it, work it, then earn real exam marks. Everything stays on the timeline below.
In this lesson — start anywhere
Geometry & measures · Perimeter, area & volume
Volume of prisms, cylinders, cones & spheres
Why a prism's volume is cross-section × length, why a cylinder is just a circular prism, where the ⅓ in pyramid and cone formulas fits in, spheres and hemispheres, and litres.
Why it works
A stack of identical slices
Volume counts unit cubes. A cuboid is layers of them. The powerful idea behind every prism is slicing: a prism is any solid with the same cross-section all the way through, so it is a stack of identical slices —A cylinder is a circular prism
Cross-section , so . The one thing to check before squaring: is the printed measurement the radius or the diameter? Halve the diameter first — squaring a diameter quadruples the answer.Keep reading — free
The rest of the explanation, plus 2 worked examples you step through move by move.
Start freeTakes a minute — no card.