a waterwheel has a radius of 5 feet. the center of the wheel is 2 feet above the waterline. you notice a white mark at the top of the wheel. how many radians would the wheel have to rotate for the white mark to be 3 feet below the waterline?

a) 2pi radians
b) 3pi/2 radians
c) pi radians
d) pi/2 radians