Question

diameter of a bicycle wheel is 28cm. what distance will it cover in 100 revolutions??

Answer 1

d = 28 cm ,
r = 14
 
c = 2πr
   = 2 x 22/ 7 x 14
    =88 cm

distance covered in 100 revolution = 88 x 100 = 8800 m

Answer 2

ok, so we have the diameter which is 28 cms
So the radius of the wheel is 28/2=14cms
so, r=14cm.

now the distance it covers in 1 revolution is 2πr
2πr=2*(3.14)*14
     =88 cms.
 so it covers the distance of 88 cms in 1 revolution. ^_^

Now, in 100 revolution it goes on the distance of....
=88*100
=8800 cms. 
hope it helped. ^_^