Question

The total surface area of a right cone is $880$ $c{m}^2$ and the radius is $7$ $cm$, then its slant height is:

• A. $33$ $cm$
• B. $15$ $cm$
• C. $23$ $cm$
• D. $13$ $cm$

Answer 1

The correct option is A $33$ $cm$

Total surface area of a cone $=\pi r(r+l)$, where $r$ is the radius of the cone and $l$ is the slant height.
Given, total surface area of a right cone is $=880c{m}^2$

$⟹$ $\frac{22}{7}\times 7\times (7+l)=880$
$⟹$ $7+l=40$
$⟹$ $l=33cm$.

Hence, option $A$ is correct.