Explain how you will measure the area of

(a) a square

(b) a leaf?

(a) Measurement of area of a square : As the area of a regular shape can be expressed in terms of the product of it's two measurements in length and since square has all side length equal then the area of a square can be calculated by using the following formulae :

Area of a square of side l = side x side = l × l = l²

(b) Measurement of area of a leaf : The area of an irregular surface like a leaf can be measured using graph paper. We count the squares of each side 1 cm, the area of which is 1 cm × 1 cm = 1 cm². This therefore gives an approximate area of the given surface.

Procedure :

1. Place the leaf on a graph paper.
2. Draw its outline on the paper and remove it.
3. Now count the number of complete squares.
4. To this add the number of incomplete squares which are half or more than half (within the outline).
5. Ignore the squares which are less than half (within the outline).
6. This number when multiplied by the area of one square gives the approximate area of the given surface. Thus,

Approximate area of a leaf = (No. of complete squares + No. of half or more than half of incomplete squares) × Area of one square