Q20 of 46 Page 1

504 cones, each of diameter 3.5 cm and height of 3 cm, are melted and recast into a metallic sphere.

Find the diameter of the sphere and hence find its surface area. (Use π = 22/7)

For one cone


Radius,


Height, h = 3 cm





Now As these 504 are melted into a sphere volume of sphere will be same as the volume of these cones.


Volume of sphere = volume of 504 cones




r3 = 1157.625


r = 10.5 cm


Diameter = 2r = 21 cm


Surface area of sphere = 4πr2



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