Consider a circle whose size can vary. the circumference of the circle is always 2π times as large as its radius. let r represent the radius of the circle (in feet) and let c represent the circumference of the circle (in feet).

a. write a formula that expresses c in terms of r.
b. use your formula from part (a) to determine the circumference of a circle whose radius is 6 feet feet
c. write a formula that expresses r in terms of c.
d. use your formula from part (c) to determine the radius of a circle whose circumference is 37