Question

The diameter of a 120 cm long roller is 84 cm. if it takes 1000 complete revolutions to level a playground having breadth of 36 m, find the length of the playground.​

Answer 1

Radius(r)=diameter/2=84/2=42cn

Height of the roller(h)=120cm

C.S.A=2πrh=2*(22/7)*42cm*120cm

=31680cm^2

Area of the playground having breath 36m(A)= l*b

3600Lcm^2

No. Of complete revolutions(N)=1000

or, C.S.A/A=1000

or,31680/3600L=1000

or,L=31680/3600000

or, L=0.0088cm/0.88m

Hence, the length of the playground is 0.88m