Question

a road roller takes 750 complete revolutions to move once over to Level road. find the area of the road if the diameter of the road roller is 84cm and its length is 1 m.

Answer 1

here.....
DIAMETER OF ROAD ROLLER=84cm

radius=1/2×diameter
we get,

radius=42cm
length=1m
i.e height=1m=100cm

when roller revolves curved surface area of cylindrical roller revolves.

Curved surface area of cylinder=2πrh
$= 2 \times \frac{22}{7} \times 42 \times 100$


$= 2 \times 22 \times 6 \times 100$
=26400sq.cm
=264sq.m

CURVED SURFACE AREA OF ROLLER
=264sq.m

NOW WHEN IT REVOLVES 750 times it covers the area of road

we can conclude,

Area of road=
750×curved surface area of roller
=750×264
=198000sq.m

THEREFORE,
$area \: of \: road \: is \: 198000 {m}^{2}$


$hope \: this \: helps$