Question

The height of a cone is $15$ cm. If its volume is $1570{\text{cm}}^3$, find the radius of the base. (Use $\pi =\frac{22}{7}$ )

Answer 1

height of the cone $h=15cm$
Volume $V=1570c{m}^3$, radius $r=?$
Volume of a cone $V=\frac{1}{3}\pi r^{2}h$
$\frac{1}{3}\pi r^{2}h=1570$
$\frac{1}{3}\times \frac{22}{7}\times r^2\times 15=1570$
$r^2=1570\times \frac{7}{22}\times \frac{3}{1}\times \frac{1}{15}$
$r^2=100$
$\therefore r=10cm$