Area of compound figures
key points :
๐ Compound Figure
- A compound figure (or composite shape) is a shape made up of two or more simple shapes.
Example: Rectangle + Triangle, Square + Circle, etc.
๐งฉ Break Into Simple Shapes
- To find the area easily, split the compound figure into simple shapes you already know:
โ Square
โ Rectangle
โ Triangle
โ Circle (if given)
๐ Area Formulas You Must Know
| Shape | Formula | Emoji |
|---|---|---|
| โฌ Rectangle | Area = Length ร Breadth | ๐ร๐ |
| โผ๏ธ Square | Area = Side ร Side | ๐ฒ |
| ๐บ Triangle | Area = ยฝ ร Base ร Height | โ๏ธโ2 |
| โช Circle* | Area = ฯ ร rยฒ (use only if required at grade level) | ๐ต |
๐ก Add or Subtract Areas
- If shapes are joined, add their areas โ
- If a part is cut out, subtract the removed area โ
๐ Steps to Find the Area of a Compound Figure
1๏ธโฃ Split the figure into smaller known shapes ๐งฉ
2๏ธโฃ Label the lengths clearly โ๏ธ
3๏ธโฃ Write formula for each shape ๐
4๏ธโฃ Find area of each part ๐ข
5๏ธโฃ Add or subtract the areas to get the total area โ
๐ฏ Important Tips
โจ Convert all units to the same unit before calculation (cm, m).
โจ The final answer should be in square units (cmยฒ, mยฒ).
โจ Draw lines to separate shapes if neededโthis makes the problem easier! โ๏ธ๐
๐ Example (Simple)
A figure is made of:
๐ 1 rectangle + 1 triangle
โก๏ธ Find area of rectangle
โก๏ธ Find area of triangle
โก๏ธ Add them to get the total area ๐
โ Remember!
- Compound = Many Shapes Combined ๐งฉ
- Area means the space inside a shape ๐
- Use formulas + addition/subtraction to find the total area ๐งฎ
Learn with an example
๐ What is the area of this figure?

__________ square centimetres
- Divide the figure into rectangles:

- Start with rectangle A. Rectangle A is 11 centimetres wide and 11 centimetres tall.
- Multiply: 1111=121
- The area of rectangle A is 121 cm2.
- Look at rectangle B. Rectangle B is 22 centimetres wide and 14 centimetres tall.
- Multiply: 2214=308
- The area of rectangle B is 308 cm2.
- Now add the areas of the two rectangles:
- 121 cm2+308 cm2=429 cm2
- The area is 429 square centimetres.
๐ What is the area of this figure?

_________square kilometres
- Divide the figure into rectangles:

- Start with rectangle A. Rectangle A is 17 kilometres wide and 13 kilometres tall.
- Multiply: 1713=221
- The area of rectangle A is 221 km2.
- Look at rectangle B. Rectangle B is 7 kilometres wide and 22 kilometres tall.
- Multiply: 722=154
- The area of rectangle B is 154 km2.
- Now add the areas of the two rectangles:
- 221 km2+154 km2=375 km2
- The area is 375 square kilometres.
๐ What is the area of this figure?

___________square millimetres
- Divide the figure into rectangles:

- Start with rectangle A. Rectangle A is 5 millimetres wide and 23 millimetres tall.
- Multiply: 523=115
- The area of rectangle A is 115 mm2.
- Look at rectangle B. Rectangle B is 17 millimetres wide and 4 millimetres tall.
- Multiply: 174=68
- The area of rectangle B is 68 mm2.
- Now add the areas of the two rectangles:
- 115 mm2+68 mm2=183 mm2
- The area is 183 square millimetres.
Let’s practice!๐๏ธ

