The area of the base of a cone is 38.5 c

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Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Mensuration: 3D

Question:

The area of the base of a cone is 38.5 cm² and the curved surface area is 143 cm². The slant height of this cone will be?

Options:

15 cm

9 cm

13 cm

12 cm³

Correct Answer:

13 cm

Explanation:

Area of base = \(\pi \)r²= 38.5

⇒ \(\pi \)r²= 38.5

⇒ r²= \(\frac{38.5 × 7}{22}\)

⇒ r = 3.5 cm

C.S.A. = \(\pi \)rl

⇒ 143 = \(\frac{22}{7}\) × \(\frac{7}{2}\) × l

⇒ l = 13 cm