if the unicycle with the largest wheel of 185 cm is ridden 1 km how many complete rotations will the wheel make

Let N be the number of rotations.

Each rotation advances the tire and the unicycle 2*pi*R

The distance traveled and the radius must use the same dimensions when using the formula.

N*2*pi*R = 1000 (meters)
R = 1.85 meters

N = (1000/1.85)*[1/(2pi)] = 86