If it travels 12.56 ft in one revolution, then the circumference of the tire is 12.56 ft. Circumference = 2 x π x radius 12.56=2 x 3.14 x radius radius x 6.28=12.56
1 revolution the part that touches the ground makes 1 full circle therefor 12.56 is the cirvmerncere circumfrence=2pir 12.56=circumfrence 12.56=2pir divide both sides by 2 6.28=pir aprox pi to 3.14 and divide both sides by 3.14 2=r