Year 10 - Maths
Checking and securing understanding of perimeter for compound shapes
2D and 3D shape: compound shapes
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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, knowledge of circles and polygons is drawn upon to find the arc length and area of a circle sector and areas of complex compound shapes.
Lesson Summary
You will learn to calculate the perimeter of compound shapes made from rectangles, triangles, parallelograms and trapeziums efficiently.
Key Notes
- Before calculating perimeter, consider the shape and check you know the required lengths.
- It is not necessary to know every side length.
- Sometimes you can deduce the sum of a subset of side lengths.
- Identifying where you can be more efficient can make calculations simpler.
Vocabulary To Learn
- Perimeter: The perimeter is the distance around a 2D shape.
- Compound shapes: A compound shape is a shape created using two or more basic shapes.
- Composite shapes: A composite shape is an alternative for a compound shape.
Common Mistakes To Avoid
- Pupils may miss an edge when calculating the perimeter.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
Before calculating perimeter, consider the shape and check you know the required lengths. It is not necessary to know every side length.
2. Use this key word in a maths sentence and explain it clearly. 'Perimeter'
The perimeter is the distance around a 2D shape. 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 miss an edge when calculating the perimeter. Correction: Encourage the pupils to trace the perimeter to check that all edges have been included in the sum.
More Lessons In This Unit
- Area of a sector Study Guide
- Area of compound shapes Study Guide
- Calculating arc length Study Guide
- Checking and securing understanding of area for compound shapes Study Guide
- Checking and securing understanding of area for standard shapes Study Guide
- Checking and securing understanding of circles Study Guide
- Checking and securing understanding of converting between metric and imperial measures Study Guide
- Checking and securing understanding of perimeter for standard shapes Study Guide
- Checking and securing understanding of scales and conversion Study Guide
- Equations from complex shapes Study Guide
- Perimeter and area in a contextual setting Study Guide
- Problem solving with 2D shapes Study Guide
- Problem solving with complex 2D shapes Study Guide
- Shapes on coordinate grids Study Guide
- Shapes within shapes Study Guide
Browse all guides in the Year 10 Maths guide library.