Cone, a hemisphere and a cylinder stand on equal bases and have the same height. The ratio of their volumes are:

A 1:2:2

B 1:2:3

C 1:2:4

D 2:3:4

E 3:2:4

Solution

Correct Answer: Option B

Since the Cone, hemisphere and cylinder have same radius and same height

Volume of the cone is given by \(= {\rm{\;}}\frac{1}{3}{\rm{\pi }}{{\rm{r}}^2}{\rm{h}}\)

Volume of the hemisphere is given by \(= \frac{2}{3}{\rm{\pi }}{{\rm{r}}^3}\)

Volume of the cylinder is given by = πr2h

∴ Ratio of their volumes = Volume of the cone: Volume of the hemisphere: Volume of the cylinder

∴ Ratio of their volumes \(= {\rm{\;}}\frac{1}{3}{\rm{\pi }}{{\rm{r}}^2}{\rm{h\;}}:{\rm{\;}}\frac{2}{3}{\rm{\pi }}{{\rm{r}}^3}:{\rm{\pi }}{{\rm{r}}^2}{\rm{h\;}}\) [∵ r = h]

⟹ Ratio of their volumes \(= {\rm{\;}}\frac{1}{3}{\rm{\;}}:{\rm{\;}}\frac{2}{3}:1 = 1:2:3\)

Practice More Questions on Our App!

Download our app for free and access thousands of MCQ questions with detailed solutions