Question

What is the approximate total surface area of a right circular cone of height 14 cm and base radius 7 cm? $\left(inc{m}^2\right)$

• A. 344
• B. 430
• C. 499
• D. 550

Answer 1

The correct option is C 499

Given,

$h=14cm,r=7cm$
Slant height $l$ is given by
$l^2=(r{)}^2+(h{)}^2$

$l^2=(7{)}^2+(14{)}^2=245\Rightarrow l=7\sqrt{5}cmTSA=\pi rl+\pi r^2=\frac{22}{7}\times (7\times 7\sqrt{5}+7\times 7)=499sq.cm$