Area of Plane Figure

Areas of plane figures

In the previous sections, you learnt to find the perimeter of a parallelogram, trapezium and circumference of a circle. In this section, you will learn to find areas of these figures.

Area of a parallelogram

Parallelograms are among the plane figures. You can recall that, some of the properties of parallelograms are: opposite sides and opposite angles are equal. But, what is the formula for calculating areas of parallelograms?

The resulting figure in the activity is a rectangle. Remember that, the area of a rectangle is calculated by multiplying its length by width. Therefore, the area of the parallelogram is the same as the area of the rectangle formed. Thus,

Area of parallelogram = length × width.

Remember that, the parallelogram has no width, but it has height. The formula for the area of the parallelogram is therefore given by:

Area of parallelogram = length × height

Example 1

Find the area of the following parallelogram:

Solution

Area of parallelogram = length × height

= $12 \text{ cm} \times 6 \text{ cm}$

= $72 \text{ cm}^2$

Therefore, the area of the parallelogram is $72 \text{ cm}^2$