Perimeter and area

Rectangle area is S = length × width. Use the same units for both lengths. If the lengths are in centimetres, express the area in cm².

The legs of a right triangle are perpendicular. Multiply their lengths and divide by 2: S = one leg × other leg ÷ 2. This is half the area of a rectangle with the same base and height.

The label P in the drawing is the perimeter, not the side length. A square has four equal sides, so divide the perimeter by 4 to find one side. Multiply that side length by itself to calculate the area. If lengths are in centimetres, give the area in square centimetres.

Calculate the area of the full large rectangle and the area of the removed small rectangle. Highlighted area = large area − removed area. If a side length is missing, find it from the difference between the marked lengths.

First find the plot perimeter: 2 × (length + width). The gate opening needs no fencing, so subtract its width from the perimeter. Express the answer in metres.

All four square sides have the same length. Multiply one side length by 4 to obtain the perimeter: P = 4 × side.

Half the rectangle perimeter equals the sum of its two different side lengths. First divide the perimeter by 2, then subtract the known side: other side = P ÷ 2 − known side.

Half the rectangle perimeter equals the sum of its two different side lengths. First divide the perimeter by 2, then subtract the known side: other side = P ÷ 2 − known side.

The perimeter is the sum of all side lengths. Opposite rectangle sides are equal, so P = 2 × (length + width). Use length units such as cm.

First find the plot perimeter: 2 × (length + width). The gate opening needs no fencing, so subtract its width from the perimeter. Express the answer in metres.