What do you call an alligator in a vest?
An investigator of course.
Lets investigate how to find the area of compound shapes including circles.
Compound shapes are shapes made up of two or more simple shapes.
All we need to know is the area of these simple shapes. Lets recap.
Area of a square/rectangle/parallelogram = base x height
Area of a triangle = base x height ÷ 2 OR 1/2 base x height
Area of a circle = π x radius x radius (πr²)
The value of Π is usually taken as 3.14 or use the Π button on your calculator.
Here you can separate this shape into a rectangle measuring 9 cm x 8 cm = 72 cm² and a semi circle.
To find the semi circle find the area of the full circle π x 3 x 3 = 28.27 now divide by 2 = 14.14 cm²
Now just add 72 cm² to 14.14 cm² = 86.14 cm²
Area of the triangle = 7 x 9 = 63 cm² ÷ 2 = 31.5 cm²
Area of the semi circle = π x 5 x 5 = 78.54 cm² ÷ 2 = 39.27 cm²
Total area = 31.5 cm² + 39.27 cm ² = 70.77 cm²
Your turn to investigate.