Question

The equation C=2(3.14)r is the formula that relates the circumference of a circle to the radius. This gives us the ability to calculate pi is we physically measure a circle's circumference and radius. Solve the equation for Pi to get the formula you would use to perform this activity.

Answer 1

Hello from MrBillDoesMath!

Answer:

r = C/6.28

Discussion:

Note that C = 2 * Pi * r is the exact formula. As Pi is approximately 3.14, the given formula, C = 2 (3.14) r, is an approximation.  Solving it for r:

C = 2(3.14) r               =>                as 2 * 3.14 = 6.28

C =  6.28 r                 =>                divide both sides by 6.28

r ( 6.28/6.28) = C/6.28 =>           as 6.28/6.28 = 1

r = C/6.28

Thank you,

MrB