Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Mensuration: 3D

Question:

Two right circular cones of equal volumes have their heights in the ratio 4 : 9. What is the ratio of the radii of their bases, the cones coming in the same order as that in which the ratio of their heights is given?

Options:

9 : 4

3 : 2

4 : 9

2 : 3

Correct Answer:

3 : 2

Explanation:

We know that,

Volume of a cone = \(\frac{1}{3}\)πr2h

Ratio of the heights of the cones =  4 ∶ 9.

Let the radius of the two cones = m and n

Also, let the heights of the cones be 4a and 9a

According to the question,

\(\frac{1}{3}\)π × m2 × 4a = \(\frac{1}{3}\)π × n2 × 9a

= 4m2 = 9n2

= \(\frac{m}{n}\) = \(\frac{3}{2}\)

Ratio of radii = 3 : 2