Question

If the area of the base of a right circular cone is 51 $m^2$and volume is 68 $m^3$ then its vertical height is

• A. 3.5 m
• B. 4 m
• C. 4.5 m
• D. 5 m

Answer 1

The correct option is B 4 m

Given the area of base of right circular cone is 51 sq m and volume is 68 cu m

Then area of base =$\pi r^2=51$

$\Rightarrow r^2=\frac{51}{\pi }$

$\therefore volume=\frac{1}{3}\pi r^{2}h=68$

$\Rightarrow \frac{1}{3}\pi \left(\frac{51}{\pi }\right)h=68$

$\Rightarrow h=\frac{68}{17}$

$\Rightarrow h=4$ m