What is the total surface area of a right circular cone of height 14 cm and base radius 7 cm?

Q: What is the total surface area of a right circular cone of height 14 cm and base radius 7 cm?

h = 14 cm, r = 7 cm. So, l = √(7)2 + (14)2 = √245 = 7√5 cm. ∴ Total surface area = Πrl + Πr2 = ❨ 22 x 7 x 7√5 + 22 x 7 x 7 ❩cm2 7 7 = [154(√5 + 1)] cm2 = (154 x 3.236) cm2 = 498.35 cm2.

344.35 cm2
462 cm2
498.35 cm2
None of these

Correct Answer: 498.35 cm2

Explanation:

h = 14 cm, r = 7 cm.

So, l = √(7)² + (14)² = √245 = 7√5 cm.

∴ Total surface area

= Πrl + Πr²

=	❨	22	x 7 x 7√5 +	22	x 7 x 7	❩cm²
		7		7

= [154(√5 + 1)] cm²

= (154 x 3.236) cm²

= 498.35 cm².

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