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## JSS1: MATHEMATICS - 2ND TERM

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#### Quizzes

Lesson 8, Topic 2
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# Area of a Rectangle

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In the previous topic, by counting, we obtained an area of 15cm2 for a 5cm by 3cm rectangle.

Notice also that 5 × 3 = 15

Thus, the area of a rectangle = “length or width” × “height”

Area =  w  ×  h

Where  w  is the width
Where  h  is the height

If Area is given then to find h or w, we use the following formula:

Area   =  w    ×    h

width, w = $$\frac{Area}{h}$$

height, h = $$\frac{Area}{w}$$

### Example 1:

Calculate the area of a rectangle of length 50cm and 30cm in width.

Solution:

Area   =  width  ×  height

= 30cm   ×     50cm

= 150cm2

### Example 2:

The area of a rectangle carpet is 20m2. Find the length of the shorter side in metres if the length of the longer side is 4000mm.

Solution:

First, we have to convert 4000mm to m (millimetres to metres)

1000mm   =  1m

So 4000mm   = $$\frac{1}{1000} \: \times \: \scriptsize 4000 \\ = \frac{4000}{1000} \\ = \scriptsize 4m$$

If A   =   w   ×     h

height h = $$\frac{Area}{w} \\ = \frac{20m^2}{4m} \\ = \scriptsize 5m$$