trig
posted by suZANNE .
a wheel has a diameter of 18 inches and makes one full turn in 12 seconds and picks up a piece of gym how high off the ground is that piece of gum 18 seconds after the wheel picked it up

think about it:
12 seconds the wheel traveled 360 degrees (or returns where it started)
so, 12 seconds + 6 seconds (18 seconds total)
 an additional 6 seconds would mean half of 12 seconds (or half of 360 degrees)