A cone has height which is half of 16.8 cm, while diameter of its base is 4.2 cm. It is melted and recast into a sphere. Find the surface area of the sphere.?

55.44 sq cm
60 sq cm
65.58 sq cm
59 sq cm

Correct Answer: 55.44 sq cm

Explanation:

Given that, Height = 1 m
Diameter = 140 cm or 140/100 m = 1.40 m
∴ r = 1.40/2 = 0.7 m
Now,
Required sheet = Total surface area = 2πr( h + r)
= (22/7) x 1.4 x (1 + 0.7) = 7.48 sq m
∴ Sheet required = 7.48 sq m

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