Question 78059
To find the arc length simply use this formula:

*[Tex \large s=\theta*r] where *[Tex \large \theta] is the angle

So lets find the arc length with the given information:

*[invoke Arc_Length 45, 12]

So our arc length is 9.424778 ft

Since the zipper goes from the center to the arc, simply add the arc length and the radius to find the total length of the zipper:

12+9.424778=21.424778 ft

So if you wanted this length rounded to the closest foot you would get:

lenght of zipper=21 ft