Ahead of discussing how to calculate the surface area of a circle, let us begin by defining what a circle is. A circle is a shape where all points in a plane lie at an equal distance from a center point.

Surface area is the sum of all the areas of all the shapes that cover the surface of an object. For instance, we can calculate the surface area of a sphere, a cone or even the surface area of a cylinder.

Since a circle is 2 – dimensional, its surface area is the same as its area. The area of a circle may be calculated when the length of its radius, diameter, or circumference is known.

The area of the circle formula is useful for measuring the space occupied by a circular field or a plot. Suppose you have the plot to fence it, then the area formula will help you to check how much fencing is required. Or suppose you have to buy a table cloth, then how many portions of cloth is needed to cover it completely.

### Formula to Calculate Surface Area of a Circle.

**Example 1:**

Calculate the surface area of a circle whose radius is 21 cm.

Therefore, the surface area of the circle is 1386 cm² .

**Example 2:**

Calculate the S.A of a circle if its diameter is 98cm.

Hence, the area of the circle is 7,546cm^{2}.