Two spheres of copper, of radii is 1cm and 2cm respectively, are melted into a cylinder of radius 1cm. Find the altitude of the cylinder.

Answer 1

for sphere, v = 4π/3 r^3
for cylinder, v = πr^2h

so, since the radius of the cylinder is 1,

4π/3 (1^3+2^3) = πh