How to Calculate the Area of a Circle

What is the formula to calculate the area of a circle?

Choose the correct formula to calculate the area of a circle:

A. \( A = \pi r^2 \)

B. \( A = 2 \pi r \)

C. \( A = \pi r \)

Answer:

The correct formula to calculate the area of a circle is A. \( A = \pi r^2 \)

To calculate the area of a circle, you need to use the formula \( A = \pi r^2 \). In this formula, \( A \) represents the area of the circle and \( r \) represents the radius of the circle.

First, determine the radius of the circle. The radius is the distance from the center of the circle to any point on the circle's circumference.

Next, square the radius by multiplying it by itself. For example, if the radius is 5 units, the calculation would be \(r^2 = 5 \times 5 = 25\).

Finally, multiply the squared radius by the value of pi (\( \pi \)), which is approximately 3.14159, to find the area of the circle. Using the previous example, the calculation would be \( A = \pi \times 25 = 78.54 \) square units.

Remember to always use the correct formula \( A = \pi r^2 \) when calculating the area of a circle!