Prisms, cuboids and cylinders
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The teaching part (1 min) is free to watch. A free account opens the whole lecture: 6 practice questions, 1 real past-paper question with the answer explained, the mistakes that lose marks, the full-marks tip, a one-card summary and a quick quiz.
What this lecture covers
- Slice it and stack it
- Volume of a prism
- A triangular prism
Read the transcript of the teaching part
Last time
Before we start: last time, in Spheres, cones and pyramids, you learned these points. Here they are again on one card. Keep them in mind, because today builds on them.
Slice it and stack it
Take a stack of identical coins, or a loaf of bread. Every slice has the same shape, so the volume is the area of one slice times the number of slices. That single idea covers cuboids, triangular prisms and cylinders. Then we look at the skin of the shape: the surface area.
Volume of a prism
A prism has the same cross-section all the way along. Its volume is the area of the cross-section times the length. A cuboid five by four by three: the cross-section is twenty, the length is three. Volume sixty. Volume is in cubic units: cubic centimetres, cubic metres.
A triangular prism
The cross-section is a triangle with base six and height four. Its area is a half times six times four: twelve. The prism is ten long. The volume is twelve times ten, a hundred and twenty cubic centimetres. Always say which face is the cross-section. It is the one shape that repeats.
How often it comes up
How often Cambridge has asked each part, counted by ExamYard from every past paper in its question bank: Cuboids and prisms.
The whole chapter: Surface Area and Volume.
Chapter 24: Volume and surface area
- Prisms, cuboids and cylinders 5 min
- Spheres, cones and pyramids 6 min
Also for O Level Maths 4024
Which topics come up most in O Level Maths 4024 past papers, counted from every paper since 2004.