47.1238898

A Circle is basically a figure that consists of a number of points that are at equal distance from the center. Diameter of a circle refers to a line that passed through the center of circle and has its end points on the circle. It is double the length of the radius of the circle. On the other hand, circumference of a circle is a number that defines the parameter of the circle.

Circumference can be mathematically written as:

C= (pie)diameter.

Putting values of circumference and pie in the above equation. We can get the value for the diameter.

15 = 3.14 (diameter)

Diameter = 15/3.14

Diameter = 4.777 ft is the required answer.