Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Numerical Ability

Topic

Ratios

Question:

In a right circular cylinder, the ratio of the curved surface to the total surface area is 3:7. Find the ratio of the height of the cylinder to the radius of its base.

Options:

3 : 4

2 : 3

3 : 2

4 : 3

Correct Answer:

3 : 4

Explanation:

Curved surface of cylinder = 2\(\pi \)rh

Total surface area of cylinder = (2\(\pi \)rh + 2\(\pi \)r

According to the question,

⇒ \(\frac{CSA}{TSA}\) = \(\frac{3}{7}\)

⇒ \(\frac{h}{h + r}\) = \(\frac{3}{7}\)

⇒ 7h = 3h + 3r

⇒ 7h - 4h = 3r

⇒ 4h = 3r

⇒ \(\frac{h}{r}\) = \(\frac{3}{4}\)

⇒ h : r = 3 : 4

Therefore, the ratio of height and radius is 3 : 4.