The circumference of the circle can be calculated using the following rule:
circumference = 2*pi*radius
We are given that:
circumference = 62.8 ft
pi = 3.14
Substitute with the givens to get the value of the radius as follows:
62.8 = 2*3.14*radius
radius = 10 ft
Now, diameter of a circle is twice its radius, therefore,
diameter = 2*10 = 20 ft