The base and height of the parallelogram describe the parts of the circle.
Let us consider B as base and H as the height of the parallelogram. Base b is equal to half of the circumference of the circle.
To determine the area of the circle, substitute r for h and πr for b in the area formula by considering r as the radius of the circle.
Therefore, the formula to find the area of a circle is πr² square units.