An Important Question of class 10 Based on Mensuration Chapter of M.L Aggarwal for ICSE BOARD.

Here given a metallic disc, in the shape of a right circular cylinder,its height base radius are given. If Metallic disc is melted and made into a sphere. Then, Calculate the radius of the sphere.

This is the Question Number 08, Exercise 17.5 of M.L Aggarwal.

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# A metallic disc, in the shape of a right circular cylinder, is of height 2.5 mm and base radius 12 cm. Metallic disc is melted and made into a sphere. Calculate the radius of the sphere.

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Given height of the cylinder, h = 2.5 mm = 0.25 cmRadius of the cylinder, r = 12 cmVolume of the cylinder = r^{2}h= Ã—12^{2}Ã—0.25= Ã—144Ã—0.25=Â36 cm^{3}Let R be the radius of the sphere.Volume of sphere = (4/3)R^{3}Since metallic disc is melted and made into a sphere, their volumes remains same.(4/3)R36^{3Â }=ÂR

^{3}Â = 36Ã—3/4R

^{3}Â = 27Taking cube root

R = 3 cm

Hence the radius of the sphere is 3 cm.