1.

A hollow sphere of internal and external radii 2 cm and 4 cm respectively is melted into a cone of base radius 4 cm. Find the height and slant height of the cone.

Answer»

Volume of a sphere = \(\frac{4}{3}\)πr3 

Volume of a cylinder = \(\frac{1}{3}\)πr2h

Given,

radius of the internal and external surfaces of a hollow spherical shell are 2 cm and 4 cm respectively. It is melted into a cone of base radius 4 cm.

⇒ Volume of material in sphere = Volume of the cone

⇒ \(\frac{4}{3}\)x π x (4- 23) = \(\frac{1}{3}\)π x 42 x h

⇒ h = 14 cm

L2 = h2 + r2

⇒ l = \(\sqrt{14^2+4^2}\)

⇒ l = \(\sqrt{212}\) = 14.56 cm



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