Question

The diagram shows a cone. The radius of its base is $2.8$ cm and its slant height is $8$cm. Find the area of its curved surface $(\pi =\frac{22}{7})$.

• A. $70.4$ cm${}^2$
• B. $80.4$ cm${}^2$
• C. $90.4$ cm${}^2$
• D. None of these

Answer 1

The correct option is A $70.4$ cm${}^2$

Given, radius $r=2.8cm$

and slant height $l=8cm$.

Then,

curved surface area $=\pi rl$

$=\frac{22}{7}\times 2.8\times 8=70.4c{m}^2$.

Therefore, option $A$ is correct.