For this we have to use the formula for the circumference of a circle:
2rπ = 2 x radius x pi
Since 2 x radius is the same as the diameter we can simplify this to give:
d x π = diameter x pi
Now, we input our known value (the diameter) and solve!
15 x π =
15π =
47.1238898
So your answer (correct to 2 decimal places) would be 47.12 inches !
