What is circumference of a circle if the diameter is 7 ft

Circumference of the circle is found using the formula 2πr. Since you have the diameter you can divide it by 2 to find the radius.

7/2 = 3.5

So the radius is 3.5. Now the circumference.

2(3.14)(3.5) = 21.98 ft

So the circumference is 21.98 ft

Hope this helps :)