STEP 1:
Use the area of a circle formula to first calculate the radius.
A= πr^2
plug in known numbers
314= (3.14)r^2
divide both sides by 3.14
100= r^2
take square root of both sides
10 feet= r
STEP 2:
find the diameter
Diameter= 2 * radius
D= 2 * 10
D= 20 feet
CHECK:
A= (3.14)(10)^2
A= (3.14)(100)
A= 314 feet squared
ANSWER: The diameter is 20 feet.
Hope this helps! :)