Question

The diameter of a road roller is 44 cm and it is 1.4 m long.

What is the area of a levelled surface when it rolls once?

• A. $1.178m^2$
• B. $1.936m^2$
• C. $1.777m^2$
• D. $2.456m^2$

Answer 1

The correct option is B

$1.936m^2$

Radius of road roller (r) = $\frac{d}{2}=\frac{44}{2}=22cm$

Height of road roller (h) = 1.4 m

= 140 cm

Area of levelled surface, when its rolls once = Curved surface area of cylindrical road roller

= $2\pi rh$

= $2\times \frac{22}{\text{/}7}\times 22\times \text{/}{140}^{20}$

= $2\times 22\times 22\times 20$

= $19360c{m}^2$

= $1.936m^2$