If the radius of the base of a right circular cylinder is halved, then keeping the height same, the ratio of the volume of the reduced cylinder to the volume of the original cylinder is:

This question was previously asked in
Bihar STET TGT (Maths) Official Paper-I (Held On: 04 Sept, 2023 Shift 2)
View all Bihar STET Papers >
  1. 2 ∶ 3
  2. 3 ∶ 4
  3. 1 ∶ 4
  4. 4 ∶ 1

Answer (Detailed Solution Below)

Option 3 : 1 ∶ 4
Free
Bihar STET Paper 1 Social Science Full Test 1
11.6 K Users
150 Questions 150 Marks 150 Mins

Detailed Solution

Download Solution PDF

Concept -

The formula for the volume of a right circular cylinder is \(V = \pi r^2h\) , where r is the radius of the base and h is the height.

Explanation -

If the radius of the base is halved, the new volume V'  of the cylinder with the halved radius becomes:

\(V' = \pi \left(\frac{r}{2}\right)^2h = \pi \frac{r^2}{4}h \)

Now, let's find the ratio of the volume of the reduced cylinder to the volume of the original cylinder:

Ratio =\( \frac{V'}{V} = \frac{\pi \frac{r^2}{4}h}{\pi r^2h} = \frac{1}{4}\)

Therefore, if the radius of the base of a right circular cylinder is halved while keeping the height constant, the ratio of the volume of the reduced cylinder to the volume of the original cylinder is \( \frac{1}{4}.\)

Hence the ratio of the volume of the reduced cylinder to the volume of the original cylinder is 1:4.

Latest Bihar STET Updates

Last updated on Jul 3, 2025

-> The Bihar STET 2025 Notification will be released soon.

->  The written exam will consist of  Paper-I and Paper-II  of 150 marks each. 

-> The candidates should go through the Bihar STET selection process to have an idea of the selection procedure in detail.

-> For revision and practice for the exam, solve Bihar STET Previous Year Papers.

More Mensuration Questions

Get Free Access Now
Hot Links: teen patti master 2025 teen patti master old version teen patti jodi teen patti gold new version teen patti master real cash