# When a 2D shape is decomposed and the parts rearranged, the areas remains the same

I can decompose a 2D shape and create a different shape from the parts and explain why the area of the new compound shape is the same as the original 2D shape.

# When a 2D shape is decomposed and the parts rearranged, the areas remains the same

I can decompose a 2D shape and create a different shape from the parts and explain why the area of the new compound shape is the same as the original 2D shape.

## Lesson details

### Key learning points

- The area of the compound shape is equal to the total areas of its parts
- 2D shapes can be decomposed and rearranged in different ways
- 2D shapes can be decomposed and rearranged in different ways but the total area stays the same

### Common misconception

Children may assume some shapes have a larger area than others by comparison of a certain dimension. In this lesson, pattern blocks can be arranged to create shapes with very different dimensions.

Encourage pupils to rearrange the composing shapes to prove that the compound shapes have the same area. This can be done effectively with tangrams or pattern blocks, both of which feature heavily in this lesson.

### Keywords

Compound shape - A compound shape is a shape created using two or more basic shapes.

Area - Area is the measurement of a flat surface. It measures a 2D space.

### Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

## Video

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