Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Mensuration: 2D

Question:

The perimeter of an equilateral triangle is equal to circumference of a circle.  The ratio of their areas is:

Options:

22 : 21\(\sqrt {3}\)

21\(\sqrt {3}\) : 63

21 : 22\(\sqrt {3}\)

21\(\sqrt {3}\) : 22

Correct Answer:

22 : 21\(\sqrt {3}\)

Explanation:

Perimeter of equilateral triangle = 3a

ATQ,

⇒ 3a = circumference of circle

⇒ 3a = 2\(\pi\)r

⇒ a : r = 2\(\pi\) : 3

Area of circle = \(\pi r^2\)

Area of equilateral triangle = \(\frac{\sqrt {3}}{4} a^2\)

Required ratio = \(\frac{\sqrt {3}}{4} a^2\)  :  \(\pi r^2\)

                       =  \(\frac{\sqrt {3}}{4}\) (2\(\pi\))2 : \(\pi\) 32

                       =  \(\pi\) : 3\(\sqrt {3}\)

                       = 22 : 21\(\sqrt {3}\)