Question

the dice of the internal and external surfaces to hollow hemispherical shell are 60 and 10 cm respectively it is melted and recast into a solid cone of diameter 14 cm, find the height of the cone

Answer 1

Volume of hollow hemisphere = Volume of cone

$\frac{2}{3} \pi$(R³-r³) = $\frac{1}{3} \pi$ r² h

(cancelling 1/3 and π)
2(216000-1000) = 7 * 7 * h
2 * 215000 = 49 h
h = 8775.5 cm