Question

The volume of a conical pencil is $4928{in}^3$. If the radius of the base is $4$ in. Find its slant height of the conical pencil. Its original height is $10$ in.

• A. $11.77in$
• B. $14.77in$
• C. $10.77in$
• D. $12.77in$

Answer 1

Answer: (C)

The radius, height and slant height form the Pythagoras triangle with slant height as the Pythagoras.

$\therefore r^2+h^2=s^2$

We know that

$r=4in$

$h=10in$

$\therefore 4^2+{10}^2=s^2$

$\Rightarrow s^2=16+100$

$\Rightarrow s^2=116$

$\Rightarrow s=\sqrt{116}$

$\Rightarrow s=10.77in$