If the area is calculated using a formula for circles (pi x r^2), what is the radius for a circle with a diameter of 20 feet?

To find the radius of a circle when given the diameter, you need to remember that the radius is half the diameter. The formula to calculate the radius from the diameter is:

Radius = Diameter / 2

In this case, the diameter is 20 feet. Dividing this by 2 gives:

Radius = 20 feet / 2 = 10 feet

Thus, 10 feet is the radius of the circle, which is the correct response. This fundamental relationship between the diameter and radius is a key concept in geometry and is essential for calculating the area of a circle using the formula pi x r^2. The other values presented do not accurately reflect this relationship; therefore, they do not represent the radius corresponding to a diameter of 20 feet.