Area

When we measure the space occupied by the surface of a figure, we are trying to find the area. The derived S.I. unit for area is the square metre. The symbol for the square metre is m². Other commonly used units for area are square millimetre, square centimetre and square kilometre.

Regular figures: Squares, rectangles, triangles, circles and parallelograms are all examples of regular figures. We can calculate the areas of regular figures by using the right formulae.

Square: area = length x length

Rectangle: area = length x breadth

Triangle: area = 1/2 x base x height

Circle: area = π x radius²

^{Parallelogram: area = breadth x height}

Irregular figures: irregular shapes that area cannot be calculated by formulas. However, we can estimate its area with the help of a square grid which sides are of known lengths.

Steps:

1. Trace the figure on a piece of graph paper and shade the area covered by the figure.

2. Tick all the shaded areas that take up more than half a square. We consider any area that is over half a square to be one unit, and leave out areas that are less than half a square.

3.Count the number of ticks. The estimated area will be the number of ticks. Example: 40 ticks will be 40unit²

^{Source: Lower Secondary Science Matters}

^{published by Marshall Cavendish Education}