Question

road roller makes 5000 revolutions in covering 22 km find the radius of the ruler

Answer 1

roller did 5000 revolution in 22 km
so 1 revolution= 22000 m ÷5000
=4.4 m
1 revolution = circumference of circle
4.4 m = 2 ×π × r
2.2 ×7= 22× r
0.7m= r

Answer 2

we can write 22km as 22000m
let the radius of road roller(cylinder) be r

road roller is in the shape of cylinder
So,
surface area of the cylinder=covered distance /
total revolution
surface area of the road roller =22000/5000

there fore surface area of road roller = 4.4
we know that surface area of road roller=
4.4=2×22/7×r×h
4.4=44/7×r×h
4.4×7/44÷h=r
there fore r is equal to 0.1×7/h=r
so r is equal to 0.7/h=r