Further examples

Many practical examples of perimeters will not be as simple as the rectangle and squares shown in Factsheet 2, but remember that perimeter is the total length of the boundary of the shape.

Example 1

Kit's allotment is this shape. Work out the perimeter. You need to know all four lengths.
      30 + 18 + 22 + 17 = 87 m.

Example 2

Dennis wants to apply an ornamental strip to the edge of this planter. How much does he need? All the sides of this regular hexagon are equal, so a single measurement is all you need.

You can work out 25 + 25 + 25 + 25 + 25 + 25 = 150cm    (= 1.5m)

or use 25 x 6 = 150cm    (= 1.5m)

Example 3

This flower bed has a low rail round it. What is its perimeter? The shape is symmetrical, so you do not need every length. Work your way round the twelve sides. Starting with the 4 m and moving round clockwise you get:

4 + 1 + 1 + 5 + 1 + 1 + 4 + 1 + 1 + 5 + 1 + 1 = 26 m

or

4 + 1 + 1 + 5 + 1 + 1 = 13
13 x 2 = 26 m