Year 8 - Maths
Perimeter of composite shapes
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 solve perimeter problems of composite shapes involving whole and/or part circles.
Key Notes
- The length of fractions of the circumference of a circle can be found.
- The perimeter of parts of a circle can be found using the formula for the circumference and reasoning.
- The perimeter of shapes made from circles and parts of circles can be found using the circumference and reasoning.
- The perimeter of composite shapes including circles can be found.
Vocabulary To Learn
- Arc: An arc is part of a curve. When describing an arc of a circle, it is part of the circle's circumference.
Common Mistakes To Avoid
- Shapes with the same area also have the same perimeter.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
The length of fractions of the circumference of a circle can be found. The perimeter of parts of a circle can be found using the formula for the circumference and reasoning.
2. Use this key word in a maths sentence and explain it clearly. 'Arc'
An arc is part of a curve. When describing an arc of a circle, it is part of the circle's circumference. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Shapes with the same area also have the same perimeter. Correction: Demonstrate that component parts being rearranged has no effect on its area, but may affect its perimeter.
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
- 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
- Volume of prisms Study Guide
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