Year 8 - Maths
Volume of prisms
Perimeter, area and volume
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
In this unit pupils extend their knowledge of shapes by exploring the properties of circles and composite shapes before developing understanding of 3-D shapes including surface area and volume.
Lesson Summary
You will learn to use the constant cross-sectional area property of prisms to determine their volume.
Key Notes
- The shape and area of the base of a prism can be found.
- The area of the cross-section multiplied by the length gives the volume of the prism.
- This can be used to find the volume of any prism.
- Unknown lengths can be found when the volume of a prism is known.
Vocabulary To Learn
- Cross-section: a 2D face made from cutting straight through any plane of a 3D object.
- Volume: the amount of space occupied by a closed 3D shape.
Common Mistakes To Avoid
- Pupils may multiply all lengths on the diagram rather than find the area of the cross-section.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
The shape and area of the base of a prism can be found. The area of the cross-section multiplied by the length gives the volume of the prism.
2. Use this key word in a maths sentence and explain it clearly. 'Cross-section'
a 2D face made from cutting straight through any plane of a 3D object. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Pupils may multiply all lengths on the diagram rather than find the area of the cross-section. Correction: Draw the cross-sectional polygon out, find the area and then multiply by the length of the prism.
More Lessons In This Unit
- Area of a circle Study Guide
- Area of composite shapes Study Guide
- Checking understanding of area Study Guide
- Checking understanding of perimeter Study Guide
- Circumference of a circle Study Guide
- Finding a length in composite shapes Study Guide
- Multiplicative relationships in circles Study Guide
- Perimeter of composite shapes Study Guide
- Problem solving with perimeter, area and volume Study Guide
- Properties of prisms Study Guide
- Surface area of cuboids Study Guide
- Surface area of cylinders Study Guide
- Surface area of prisms Study Guide
- Using the formula for the area of a circle Study Guide
- Volume of cylinders Study Guide
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