How do I solve this trig problem?!?!?

Speed of a Car- The wheels of a car have radius 11 in. and are rotating at 600 rpm. Find the speed of the car in mi/h.



Please tell me how to solve this problem. Thanks. =)
How do I solve this trig problem?!?!?
11%26quot; = Dia. of 22%26quot;

Circumference = Pi x Dia. = 3.14159 x 22%26quot; = 69.115%26quot;/12 = 5.76'

RPM = 600

Distance per minute = 600 x 5.76' = 3456'

Dist. per hour = 3456' x 60 = 207,360'

1 mile = 5,280'

Miles per hour = 207,360' / 5,280' = 39.27 MPH