Question

Find the total surface area of a cone, if its slant height is 21 m and diameter of its base is 24 m. $[Assume\pi =\frac{22}{7}]$

Answer 1

Radius (r) of the base of the cone $=\left(\frac{24}{2}\right)m=12m$
Slant height (l) of the cone = 21 m
Total surface area of the cone = $\pi r(l+r)$
$=[\frac{22}{7}\times 12\times (12+21\left)\right]m^2$
$=(\frac{22}{7}\times 12\times 33)m^2$
$=1244.57m^2$