Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Mensuration: 2D

Question:

Find the surface area of a sphere of diameter 21 cm. (Use $π =\frac{22}{7}$)

Options:

988 cm2

1234 cm2

1445 cm2

1386 cm2

Correct Answer:

1386 cm2

Explanation:

We have,

The diameter of a sphere = 21 cm.

Then the radius = \(\frac{21}{2}\) = 10.5 cm

We know that,

Surface area of a sphere = 4πr2

= 4 × \(\frac{22}{7}\) × (10.5 )2

= \(\frac{88}{7}\) × 110.25

= 1386 cm2