Perimeter

Perimeter is the distance around a closed figure. Perimeters can be measured in millimetres (mm), centimetres (cm), metres (m) and kilometres (km). These units are related as follows: Perimeters of the following figures are often required to solve real world problems.
Perimeter of a Square Recall that:
The perimeter, P, of a square is given by the formula: P = 4s where s is the length of any side of the square.
Example 1 Find the perimeter of a square paddock of side 35 m. Solution:
So, the perimeter is 140 m.

Perimeter of a Rectangle
The perimeter, P, of a rectangle is given by the formula P = 2(l + w) where l is the length and w is the width of the rectangle.
Example 2 Find the perimeter of a rectangular field of length 50 m and width 40 m. Solution:
So, the perimeter is 180 m.

Perimeter of a Triangle
The perimeter, P, of a triangle is given by the formula: P = a + b + c where a, b and c are the side lengths of the triangle.
Example 3 Find the perimeter, P, of the triangle shown. Solution: So, the perimeter is 24 cm. Example 1