Question

a road roller is 140 cm long. its diameter is 84cm. it takes 1000 complete revolutions once over to level the road .find the cost of levelling the road at rupees 5400 m square

Answer 1

hope this helps you ......

Answer 2

here.....
road roller is 140 cm long
so,height of cylindrical roller=140cm

diameter=84cm
we know that ,
radius =1/2×diameter

so ,we get,
radius of cylindrical roller=42cm

when a road roller revolves around the road to level the road its curved surface area is involved.

Curved surface area of cylinder=2πrh
$= 2 \times \frac{22}{7 } \times 42 \times 140$

$= 2 \times 22 \times 6 \times 140$

$= 264 \times 140$

$= 36960 {cm}^{2}$

to level the road roller takes complete 1000 revolutions.
i.e curved surface area is revolved 1000times to cover area of road.

area of road=1000×36960
=36960000sq.cm

we know that
1m=100cm

so
area of road=369600sq.m

cost of levelling
=5400×369600
=₹1995840000

hope this helps!!!