Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Mensuration: 3D

Question:

If the base radius of a cone is 7 cm and height of it is 14 cm, then:

A. Slant height = $6\sqrt{5}$cm

B. Slant height = $7\sqrt{5}$cm

C. Volume = 718.67 cm3

D. Volume = 708.66 cm3

E. Ratio of height and slant height = $2:\sqrt{5}$

Choose the correct answer from the options given below:

Options:

A, C and D only

B, C and E only

B and C only

A, C and E only

Correct Answer:

B, C and E only

Explanation:

i) Slant height of cone = \(\sqrt {r^2 + h^2}\) = \(\sqrt {7^2 + 14^2}\) = \(\sqrt {49 + 196}\) = \(\sqrt {245}\) = 7\(\sqrt {5}\)

ii) Volume = \(\frac{1}{3}\) \(\pi \)r2h = \(\frac{1}{3}\)  × \(\frac{22}{7}\) ×7 × 7 × 14 = 718.67

iii) Ratio of height and slant height = 14 : 7\(\sqrt {5}\) = $2:\sqrt{5}$

Therefore,

B, C and E only are correct.