A bicycle tyre has a 40cm radius. If the wheel travels through 1 complete revolution, how far has the bicycle travelled

1 complete revolution means you have to find the circumference of the bicycle tyre.

Assume that the bicycle tyre is a circle.

Circumference of the bicycle tyre 

= 2 x pi x 40 cm

= 80 pi cm.

Therefore the bicycle has travelled 80 pi cm.