How do you calculate the area of a circular area with a 20-foot diameter?

To calculate the area of a circular area, you use the formula ( \pi r^2 ), where ( r ) is the radius of the circle. The radius is half of the diameter. In this case, a circle with a 20-foot diameter has a radius of 10 feet (since 20 feet divided by 2 equals 10 feet).

When you substitute the radius into the formula, it becomes ( \pi \times (10 \text{ feet})^2 ). This expression can be simplified to ( 10 \text{ feet} \times 10 \text{ feet} \times \pi ), which is the same as saying the radius squared times ( \pi ).

Using 3.14 as an approximation for ( \pi ), the calculation follows as ( 10 \times 10 \times 3.14 ), which corresponds to the choice stating "Radius x Radius x 3.14." Thus, this method accurately reflects the geometry of a circle and provides the correct approach to finding the area for circles based on their radius.