Area of composite shapes
Find the area of composite shapes by splitting them into rectangles, triangles and semicircles.
Worked examples
Area of an L-shaped figure
Straightforward
Problem
An L-shaped figure is formed by taking a rectangle and removing a rectangle from one corner. Find the area.
1
Find the area of the large rectangle.
2
Find the area of the removed rectangle.
3
Subtract the removed area from the large rectangle.
Answer
Area of a shape with a triangle
Moderate
Problem
A composite shape consists of an rectangle with a triangle of base and height on top. Find the total area.
1
Find the area of the rectangle using .
2
Find the area of the triangle using .
3
Add the two areas to find the total.
Answer
Area of a shape with a semicircle
Challenging
Problem
A composite shape is formed by a rectangle with a semicircle of diameter attached to one of the shorter ends. Find the total area to 2 decimal places.
1
Find the area of the rectangle.
2
Find the radius of the semicircle. The diameter is , so the radius is .
3
Find the area of the semicircle using .
4
Add the two areas to find the total.
Answer
Practise
Q1·Straightforward
An L-shaped figure is formed by taking a rectangle and removing a rectangle from one corner. Find the area in m².
Explanation
Q2·Straightforward
A composite shape is made of two rectangles joined together. One rectangle measures and the other measures . Find the total area in cm².
Explanation
Q3·Straightforward
An L-shaped figure is formed by taking a rectangle and removing a rectangle from one corner. Find the area in cm².
Explanation
Q4·Straightforward
A step-shaped figure consists of two rectangles. The upper rectangle measures and the lower rectangle measures . Find the total area in m².
Explanation
Q5·Moderate
A composite shape is formed by a rectangle with a triangle of base and height removed from the top edge. Find the remaining area in cm².
Explanation
. . Area .
Q6·Moderate
A composite shape consists of an rectangle with a triangle of base and height attached to one end. Find the total area in m².
Explanation
. . Total .
Q7·Moderate
A rectangle has a right triangle with base and height removed from one corner. Find the remaining area in cm².
Explanation
. . Area .
Q8·Moderate
A composite shape is formed by a rectangle with a triangle of base and height placed on top. Find the total area in m².
Explanation
. . Total .
Q9·Challenging
A composite shape is formed by a rectangle with a semicircle of diameter attached to one of the shorter ends. Find the total area to 2 decimal places in cm².
Explanation
. The semicircle has radius , so . Total .
Q10·Challenging
A square with side length has a semicircle of diameter removed from one side. Find the remaining area to 2 decimal places in m².
Explanation
. The semicircle has radius , so . Remaining area .
Q11·Challenging
A composite shape is formed by an rectangle with a semicircle of diameter attached to one of the longer sides. Find the total area to 2 decimal places in cm².
Explanation
. The semicircle has radius , so . Total .
Q12·Challenging
A stadium-shaped figure is formed by a rectangle with a semicircle of diameter attached to each of the shorter ends. Find the total area to 2 decimal places in m².
Explanation
. The two semicircles (radius ) together form a full circle: . Total .