The rotate volume of that shaded part is the volume of the frustum of a cone minus the volume of half a sphere.

Solution: truncated cone volume formula: v = [s+s'+√ (ss')] h ÷ 3 = π h (r+RR+r)/3.

So V =π*4*(2+2*5+5 )/3=68π/3.

The volume formula of a sphere is v = 4/3 * r 3 * π.

So V-sphere = 4/3 * 2 3 = 32 π/3. V hemisphere = 16π/3

So V Yin =68π/3- 16π/3=52π/3.

Finally, write down the unit.

This is a red tick. . .

Hope to adopt.