The area of a circle is the amount of space contained within its boundary. It is calculated using the formula A = πr², where A represents the area, π (pi) is a constant approximately equal to 3.14, and r is the radius of the circle. The radius is the distance from the center of the circle to any point on its edge. To find the area, you first measure the radius. Then, you square that number (multiply it by itself) and multiply the result by π. This gives you the total area, which is expressed in square units, such as square meters or square inches.