Question

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

Answer 1

Diameter of Roller = 84 cm

Radius of Roller = 42 cm

Length of the Roller = 100cm

The shape of a Roller is like a Cylinder.

Hence,

The Curved Surface Area of the Cylinder is as follows :-

$= 2\pi rh \\ \\ = 2 \times \frac{22}{7} \times 42 \times 100 \\ \\ \\ = 44 \times 600 \\ \\ \\ = 26400{cm}^{2}$

$\rule{200}{2}$

Number of Revolutions = 750

Total area covered =

$750 \times 2.64 \\ \\ \\ = 75 \times 26.4 \\ \\ \\ = 1980 {m}^{2}$

$\rule{200}{2}$

Therefore,

The area of the road is 1980 m²

Answer 2

Answer :--------

Surface Area of the Cylinder

$\begin{lgathered}= 2\pi rh \\ \\ = 2 \times \frac{22}{7} \times 42 \times 100 \\ \\ \\ = 44 \times 600 \\ \\ \\ = 26400{cm}^{2}\end{lgathered}$

=2πrh

Then ,

=2× 722 ×42×100

=44×600

=26400cm ²

Revolutions = 750

Total area covered

$\begin{lgathered}750 \times 2.64 \\ \\ \\ = 75 \times 26.4 \\ \\ \\ = 1980 {m}^{2}\end{lgathered}$

750×2.64

=75×26.4

=1980m ²

hope it helps ==