Adding & Subtracting Areas (Cambridge (CIE) IGCSE International Maths)

Adding & Subtracting Areas

What is a compound shape?

• Sometimes you will have a shape that is not a standard shape such as a rectangle, triangle, trapezium etc.

  • These are often called compound shapes

  • We can split the non-standard shape into standard shapes

How do I find the area of a compound shape?

• Split the compound shape into standard shapes

• Find the areas of the standard shapes

• Add these areas together to find the area of the compound shape

• Occasionally it may be easier to add an extra shape to the diagram and subtract the area of the extra shape from the new bigger shape

  • For the shape below you might complete the rectangle by putting a triangle in the top right corner

  • The area of the original shape is the rectangle minus the triangle