Question

The diameter of the base of a right circular cylinder is $21cm$ and its height is $10cm$ . What is the area of the curved surface?

• A. $660{cm}^2$
• B. $930{cm}^2$
• C. $1320{cm}^2$
• D. $640{cm}^2$

Answer 1

The correct option is A $660{cm}^2$

$Diameter=21cm$

$Radius=\frac{21}{2}cm$

$Height=10cm$

We know that the curved surface area of the cylinder

$=2\pi rh$

$=2\times \frac{22}{7}\times \frac{21}{2}\times 10$

$=220\times 3$

$=660c{m}^2$