Question

A rectangular sheet of metal $66m\times 14m$ is rolled along its length and a cylinder is formed. Find the surface area of the cylinder. ( Use $\pi$ = 22/7)

• A. 1500 $m^2$
• B. 1617 $m^2$
• C. 1400 $m^2$
• D. 1200 $m^2$

Answer 1

The correct option is B 1617 $m^2$

Height of the cylinder is 14 m
Circumference of the base = $2\pi r$
$2\pi r=66$
$2\times \frac{22}{7}\times r=66$
r = $\frac{66\times 7}{2\times 22}=10.5$
$\therefore$ Surface area of the cylinder $=2\pi rh+2\pi r^2$
$=2\times \frac{22}{7}\times 10.5\times 14+2\times \frac{22}{7}\times {10.5}^2$
$=66\times 14$
$=924+693$
$=1617m^2$