What is the area in square feet from a radius of 70 feet?what is the formula

The formula for the area of a circle is

π  times  radius ^ 2

You can use 3.14 for the value of Pi (π)

So, in your case the calculation is:

3.14 x 70 x 70 = 15,386

Since your radius was measured in feet, the answer is in square feet.

15, 386 sq. ft.