What Is Area ? Area is the amount of space inside a shape: Area Area 1cm Area is measured in square centimetres. 1cm2 A square centimeter is a square measuring one centimeter in each direction. It is written as :

Estimating The Area B A C D Look at the four shapes below and use your judgement to order them from smallest to largest area: A B C D

B A C D To decide the order of areas consider the four shapes again: To measure the area we must determine how many square centimeters are in each shape: Each shape is covered by 36 squares measuring a centimeter by a centimeter. We can now see that all the areas are equal at 36 cm2 each.

Area Of A Rectangle. Look again at one of the shapes whose area we estimated: C Length Width What was the length of the rectangle ? 9cm How many rows of 9 squares can the width hold ? 4 We can now see that the area of the rectangle is given by 9 x 4. The formula for the area of a rectangle is: A = LW for short. Area = Length x Width or

We can now calculate the area of each rectangle very quickly: (1) (2) A= L x W A = 12 x 3 =36 cm2 (3) A= L x W A = 6 x 6 =36 cm2 A= L x W A= L x W (4) A = 18 x 2 =36 cm2 A = 9 x 4 =36 cm2

Example 1 Calculate the area of the rectangle below: (2) 3m 5m 7cm 4cm (1) Solution This area is in square meters: 1m A = LW Solution A = LW L = 7 W = 4 L = 3 W = 5 A = 7 x 4 A = 3 x 5 A = 28 cm2 A = 15 m2

Example 3. Solution. 8cm 2cm 5cm 3cm Split the shape up into two rectangles: A1 Calculate the area of A1 and A2. A2 2 A1 A2 3 5 6 Calculate the area of the shape above: Area = A1 + A2 Area = ( 2 x 5) + (6 x 3) Area = 10 + 18 Area = 28cm2

What Goes In The Box ? Find the area of the shapes below : (1) 8cm 6cm (2) 48cm2 (3) 17cm 8cm 12cm 5cm 11.34m2 141cm2