How to Calculate the Area of a Circle

Last week, we have discussed how to calculate the circumference of a circle. In this post, we learn how to calculate the area of a circle. The area of a circle which we will denote by $A$ is equal to the product of $\pi$ and the square of its radius $r$. Putting it in equation, we have

$A = \pi r^2$.

In the examinations, the value of $\pi$ is specified. They usually use $3.14$, $3.1416$ or $\frac{22}{7}$.

If you can recall, the radius is the segment from the center to the point on the circle as shown below. The radius is half the diameter. The diameter is the longest segment that you can draw from one point on the circle to another. It always passes through the center.

Note: We also use the term radius to refer to the length of the radius and diameter as the length of the diameter.   Continue Reading