Unit 9 Section 4 : Area of Compound Shapes

In this section we look at ways of finding the area of shapes which are made up from other shapes.

Example Question

Look at the shape below.

If we want to find the area of the shape, we can split it into rectangles, then add together the areas of the rectangles.
Click on the shape once to see it divided up with all measurements marked.

Click here to see the shape divided into rectangles Practice Questions
Work out the answer to each of these questions then click on the button marked Click on this button below to see the correct answer to see whether you are correct.

Remember : click on the shape to see it divided up.

(a) What is the area of rectangle A?

(b) What is the area of rectangle B?

(c) What is the area of rectangle C?

(d) What is the total area of the shape?

 

Exercises

Work out the answers to the questions below and fill in the boxes. Click on the Click this button to see if you are correct button to find out whether you have answered correctly. If you are right then will appear and you should move on to the next question. If appears then your answer is wrong. Click on to clear your original answer and have another go. If you can't work out the right answer then click on Click on this button to see the correct answer to see the answer.

Question 1
Find the area of these shapes. One square on the grid is 1 cm².

(a) cm²

(b) cm²

Question 2
Find the areas and perimeters of the shapes below.
The diagrams have not been drawn accurately, so you may find it helpful to sketch them on paper.

(a)
Area = cm²
Perimeter = cm
(b)
Area = mm²
Perimeter = mm
(c)
Area = cm²
Perimeter = cm
(d)
Area = cm²
Perimeter = cm
(e)
Area = mm²
Perimeter = mm
(f)
Area = cm²
Perimeter = cm

Question 3
Work out the shaded area in each of the diagrams below.
HINT: You may find it easiest to work out the area of the unshaded part and subtract it from the area of the outer rectangle.
 

(a) cm²

 

(b) cm²

 

(c) cm²

 

(d) cm²

Question 4
Find the areas and perimeters of the shapes below.
The diagrams have not been drawn accurately, so you may find it helpful to sketch them on paper.

(a)
Area = cm²
Perimeter = cm
(b)
Area = cm²
Perimeter = cm


You have now completed Unit 9 Section 4
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Produced by A.J.Reynolds January 2001