The area of the base of a right circular cone is 154 cm2

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The area of the base of a right circular cone is 154 cm² and its height 14 cm. The curved surface of the cone is ?

1. (154 x √2 ) cm²
2. 11 cm²
3. (154 + √7 ) cm²
4. 5324 cm²

Correct Option: A

∵ 22/7 x r² = 154
⇒ r² = 154 x (7/22) = 49
∴ r = 7 cm and h = 14
So, l = √(7)² + (14)² = √245 = 7√5 cm

∴ Area of curved surface = πrl
= (22/7) x 7 x 7√5 cm²
= 154√5 cm²