Radius of two cylinders are in the ratio of 2:1 and their volumes are equal. The ratio of their heights will be?

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  1. 1:4
  2. 3:4
  3. 1:6
  4. 1:2

Answer (Detailed Solution Below)

Option 1 : 1:4
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Given:

  • The radii of two cylinders are in the ratio 2:1.

  • The volumes of the two cylinders are equal.

  • We need to find the ratio of their heights.

Concept Used:

The volume of a cylinder is given by the formula:

Volume (V) = π × r2 × h

Here, r is the radius and h is the height of the cylinder.

If the volumes are equal, we can equate their formulas and solve for the ratio of their heights.

Calculation:

Let the radii of the two cylinders be r1 and r2, and their heights be h1 and h2.

From the problem,

r1 : r2 = 2 : 1,

so r1 = 2r2.

The volumes of the two cylinders are equal, so:

π × r12 × h1 = π × r22 × h2

Cancel π from both sides:

r12 × h1 = r22 × h2

Substitute r1 = 2r2:

(2r2)2 × h1 = r22 × h2

Simplify:

4r22 × h1 = r22 × h2

Cancel r22 from both sides:

4h1 = h2

Rearrange to get the ratio of heights:

h1 : h2 = 1 : 4

Conclusion:

∴ The ratio of their heights is 1:4.

Latest Army Havildar SAC Updates

Last updated on Jul 1, 2025

-> The Indian Army has released the Exam Date for Indian Army Havildar SAC (Surveyor Automated Cartographer).

->The Exam will be held on 9th July 2025.

-> Interested candidates had applied online from 13th March to 25th April 2025.

-> Candidates within the age of 25 years having specific education qualifications are eligible to apply for the exam.

-> The candidates must go through the Indian Army Havildar SAC Eligibility Criteria to know about the required qualification in detail. 

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