Question

Find the volume of a cone-shaped figure if its base has a radius of 7 cm and its slant height is 25 cm.

Answer 1

Radius of cone (r) =7 cm
Height of cone (h) =?
Slant height of cone (l) = 25 cm
The height and radius of a cone form a right angle.
By Pythagoras Theorem,
l² = r² + h²
⇒ 25² = 7² + h²
⇒ h² = 25² − 7²
⇒ h² = 625 − 49
⇒ h² = 576
⇒ h = 24 cm

Volume of cone =$\frac{1}{3}\mathrm{\pi }{r}^{2}h$
$$\begin{gathered} =\frac{1}{3}\times \frac{22}{7}\times 7\times 7\times 24 \\ =1232\mathrm{cu}\mathrm{cm} \end{gathered}$$