Help with math problem stuck ]:?

For C: its a cylinder with a hemisphere on top. h is total height and r is radius. radius of cylinder will be equal to the radius of hemisphere..

so, heiht of only the cylinder is (h-r)..

so total volume would be (volume of cylinder + volume of hemisphere)

i.e., PI*r^2*(h-r) + 2/3 * PI*r^3

simplify the above and u'll get Pi*r^2(h-r/3) which is the required formula..

For D, i didnt really understand the figure.but if its a rectangular cube with pyramid on top.

then total volume: (volume of the cube+volume of pyramid)

k*m*n + 1/3 * Base area(i.e. m*n)*h

simplify u'll get : m*n(k+h/3)

btw, u dont need numbers.. question only says to derive formula..