Question

How do find the area of a composite shape

Answer 1

Answer:

By breaking it down into simpler shapes.

Step-by-step explanation:

Let's take a look at this example:

A circular shaped garden of radius 15m contains a square concrete region of side length 4m . Work out the area of the grass (shaded green region).

This composite shape is made up of a circle and a square.

First work out the area of the square. You can find the area of the square by multiply the base length by the height (both are 4m)

Area of the square = 4 × 4 = 16 m²

Secondly, you can work out the area of the circle using the formula A = ∏r². The radius of the circle is given at the start of the question (r = 15m)

Area of the circle = ∏ × 15² = 706.9 m²

So there area of the grass can be found by subtracting the area of the square from the area of the circle.

Area of composite shape = 706.9 – 16 = 690.9 m²

So this is the area of grass section of the garden.

So if you are finding areas of composite shapes then you just need to break up the shape into smaller shapes. Once these are found you either add or subtract these areas to give the area of the whole composite shape.