Trigonometry
posted by Laura .
A water wheel has a radius of 15 ft. A river passing through the water wheel turns the wheel at 11 revolutions per minute(rpm). What is the speed of the river in miles per hour?

C = pi*2r = 3.14 * 30 = 94.25 Ft. =
Circumference.
V=11rev/min*94.3Ft/rev^1mi/5280Ft*60min/h = 11.8 mi/h