The perimeter of a shape is the distance around its boundary. This is a length, and is said to have \({1}\) dimension (1D).

Sometimes shapes can be more complicated. Be particularly careful to add up the lengths of every side when you work out the total perimeter. Perimeter \(= 2 + 2 + 3 + 3 + 5 + 5 = 20~cm\) In some cases ...