A circle has a radius of 7inches what is the the circle's circumference?

Remember and commit to memory.

C = 2 pi r or C = pi d

A = pi r^(2)

Where C = Circumference

A = Area

pi is a constant at 3.1416

r = is the radius

d is the dianter ; 2r = d

r^(2) = r x r = 'r' squared.

So selecting r = 7 inches

Then C = 2* (3.1416)* 7

C = 14*3.1416

C = 43.98229....

C ~ 43.99 inches.

NB In school you may be given pi =

pi = 3.14, 3.1416, 22/7

These are only approximations, but given for ease of calculating.

pi = 3.141592.... Is an irrational number and the decimals recur to infinity, AND are in no regular numerical order.