Area

A straight line has only one dimension, its length. Once we draw more lines in different directions to form an enclosed shape, we create something in 2 dimensions. In order to describe this we need more than just the length of each line, we also need to know how much space on a flat surface it takes up. This is known as its area, and we include the word ‘square’ in its units, such as cm² (square centimeters) and m² (square meters).

To be successful when solving area problems, you need to know a few formulae. The most common ones are for the rectangle (and therefore the square too), the triangle and the circle.

Complex shapes are made by combining these basic shapes, so be prepared to draw diagrams and split a shape up into rectangles and triangles. This may mean you have to work out some missing lengths.

In triangle problems, you may not know one of the perpendicular heights, but instead be given the hypotenuse. Don’t fall into the trap of using that number in your area calculation – you need to apply Pythagoras’ Theorem first, to find the shorter side.

A common type of question used in exams involves tiling an area. Usually the tiles’ dimensions are given in cm, while the area to be tiled is given in m². You need to convert the tile lengths to meters, before working out the area of each tile. Remember to apply a common sense check to your final answer – if it doesn’t look like a reasonable answer, you have probably made a mistake with your units!