Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Mensuration: 3D

Question:

The base of a right prism is an equilateral triangle of inradius 3 cm. Find the volume of the prism, if its height is 15cm -

Options:

233.82 cm³ 

256.63 cm³

701.46 cm³

720.65 cm³

Correct Answer:

701.46 cm³

Explanation:

Inradius of an equilateral triangle = \(\frac{a}{2\sqrt {3}}\)

⇒ 3 = \(\frac{a}{2\sqrt {3}}\)

⇒ a = 6\(\sqrt{3}\) cm

Area of a triangle = \(\frac{\sqrt {3}}{4}\) a2

 = \(\frac{\sqrt {3}}{4}\) × 36 × 3

 =  27\(\sqrt{3}\) cm2

volume of prism = area of base × height

 = 27\(\sqrt{3}\) × 15 = 701.46 cm2