Area Of Sha p es.

1. 2cm 12m A1 A2 7cm 10m 5cm A1 3cm 12cm A2 16m 8cm Area Of Shapes.

2. 1cm2 1cm 1cm 1cm2 What Is Area ? Area is the amount of space inside a shape: Area Area Area Area Area Area Area Area Area Area Area Area Area Area Area Area Area Area Area Area Area is measured in square centimetres. A square centimetre is a square measuring one centimetre in each direction. It is written as :

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

4. 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 centimetres are in each shape: Each shape is covered by 36 squares measuring a centimetre by a centimetre .We can now see that all the areas are equal at 36cm2 each.

5. Height Base C Area Of A Rectangle. Look again at one of the shapes whose area we estimated: What was the length of the base of the rectangle ? 9cm How many rows of 9 squares can the height 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: or A(rect) = b x h Area of a Rectangle = Base x Height

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

7. (1) (2) 4cm 5m 7cm 3m 1m 1m Example 1 Calculate the area of the rectangle below: Solution This area is in square metres: A(rect) = b x h Solution A(rect) = b x h = 7 x 4 = 3 x 5 = 28cm2 = 15m2

8. 2cm 5cm A1 A1 3cm A2 A2 8cm Example 3. Solution. Split the shape up into two rectangles: Calculate the area of A1 and A2. 2 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

9. (1) (2) 6cm 2.7m 8cm 4.2m 17cm (3) 5cm 12cm 8cm What Goes In The Box ? Find the area of the shapes below : 48cm2 11.34m2 141cm2