A bicycle wheel with radius 26" rotates through an arc that measures 80°. What is the length of the arc of the tire that touched the ground?

Question

anonymous · Answer

This would be a pretty easy question if it just asked for the circumference of the wheel, because we have a nice, easy formula for circumference: 2*pi*radius.

But arc length is some PART of a circumference.  That doesn't make the problem too much harder. You just have to find the entire circumference, and then multiply by the fraction of the circle you actually care about.  Since you only care about 80 out of the 360 degrees of the circle, take the circumference and multiply it by 80/360.