Question

From a circle of radius 15cm, a sector with angle 216 degrees is cut and it’s bounding radii are bent as to form a cone. Find it’s volume.

Answer 1

R=15 cm
x=216
R=slant height of cone(l)
\frac{r}{l} = \frac{x}{360} \\ \frac{r}{15} = \frac{216}{360} \\
r= \frac{216}{360} *15 \\ \\ r=9
height²=l²+r²=225+81=306
h=√306
volume= \frac{1}{3} \pi 9^{2} \sqrt{306} \\ 27* \pi *\sqrt{306}=1483.79