Question

The curved surface area of a cone is $12320c{m}^2$. If the radius of its base is $56cm$, find its height.

Answer 1

Given:

radius of the base of the cone $=56cm$

We know that curve d surface area of a cone$=\pi rl.$

Given that curved surface area of a cone$=12320.$

$\pi rl=12320$

$\frac{22}{7}\ast 56\ast l=12320$

$22\ast 8\ast l=12320$

$176\ast l=12320$

$l=\frac{12320}{176}=70.$

We know that height of the cone,

$h=\sqrt{l^2-r^2}$

$=\sqrt{{70}^2-{56}^2}$

$=\sqrt{4900-3136}$

$=\sqrt{1764}$

$=42.$

Therefore the height of the cone $=42m.$