Year 4 - Maths
Understand that different shapes can have the same perimeter
Perimeter
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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 pupil will learn perimeter as the distance around the edge of a 2D shape. They will learn perimeter is measured in units of length found by counting units and by calculating by adding the side lengths of a 2D shape.
Lesson Summary
You understand that different 2D shapes can have the same perimeter.
Key Notes
- Shapes that look different can have the same perimeter.
- You can draw or create more than one 2D shape with the same perimeter.
- Shapes with different numbers of sides can have the same perimeter.
Vocabulary To Learn
- Polygon: A polygon is a 2D shape made up of 3 or more straight lines.
- Perimeter: The distance around a two-dimensional shape.
Common Mistakes To Avoid
- Pupils will most likely understand that different shapes can and most often do have different perimeters. They may not realise that the perimeters can potentially be the same.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
Shapes that look different can have the same perimeter. You can draw or create more than one 2D shape with the same perimeter.
2. Use this key word in a maths sentence and explain it clearly. 'Polygon'
A polygon is a 2D shape made up of 3 or more straight lines. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Pupils will most likely understand that different shapes can and most often do have different perimeters. They may not realise that the perimeters can potentially be the same. Correction: Allowing pupils to recreate perimeters using string or number rods and rearranging themselves to make a new shape is a powerful way of showing that different shapes can have equal perimeters.
More Lessons In This Unit
- Calculate the side length of a regular polygon by division where the perimeter is known Study Guide
- Know that a regular polygon has sides that are the same length and angles that are the same size Study Guide
- Know that perimeter can be calculated by adding together the side lengths of a 2D shape Study Guide
- Know that perimeter is measured in units of length and can be found by counting or measuring units Study Guide
- Know that the perimeter is the distance around a 2D shape Study Guide
- Know that the perimeter of a rectangle can be calculated by addition and multiplication Study Guide
- Know that unknown side lengths can be calculated from the perimeter and known side lengths Study Guide
- Solve problems involving the perimeter and side lengths of polygons Study Guide
- Understand that the perimeter of a regular polygon can be calculated by multiplication Study Guide
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