💯 Maths

How do you work out perimeter?

1 answers
Sebastian Dows-MillerExperienced language tutor and Oxbridge mentor with over 200 hours experience17.5k students helped

The perimeter of a shape is essentially just the combined length of its edges, so the simplest way to work out a perimeter is to work out the lengths of the edges and add them together. For equal-sided shapes like squares, this is just a case of working out the length of one side and multiplying that number by the total number of sides (in the case of a square: 4). To work out the perimeter of a circle, you should use the equation 2πr, where π is the constant ‘pi’ (3.14159...) and r is the radius of the circle (the distance from the centre to the outer edge).