Question

If the base radius and slant height of a right circular cone are $10cm$ and $3.5cm$ respectively, then its total surface area is:

• A. $424.159c{m}^2$
• B. $434.159c{m}^2$
• C. $414.159c{m}^2$
• D. None of these
  

Answer 1

The correct option is A $424.159c{m}^2$

Given the radius of the base of a right circular cone $\left(r\right)=10$ cm, and its slant height $\left(l\right)=3.5$ cm.

Then its total surface area $=\pi r^2+\pi rl$

$=\frac{22}{7}\times 100+\frac{22}{7}\times 10\times 3.5$

$=314.159+110$

$=424.159$ $c{m}^2$.

Hence, option $A$ is correct.