Manipulate[Graphics3D[{Text[Style["r",{Medium,Italic}],{4.1+r,5.5,L}],Text[Style["(Subscript[r, in])",Medium],{5,4+k r,L}],Line[{{5,5,L},{5+r,5,L}}],Line[{{5,5,L},{5,5+k r,L}}],Line[{{5+r,5,-L},{5+r,5,L}}],Text[Style["L",{Medium,Italic}],{5+r,5+r,0}],Text[Style[Row[{"Mass = ",Round[π r 2 L (1.8-0.8 (k^2)),1],"g"}] ,Large],{5,5,17}],{White,Cylinder[{{5,5,-L},{5,5,L}},r]},{Yellow,Cylinder[{{5,5,-L},{5,5,L+0.001}},k r]}},PlotRange->{{0,11},{0,11},{-15,15.1}},Boxed->False],{{k,.5},.1,.8, Appearance-> "Labeled"},{{L,12},8.5,15, Appearance-> "Labeled"},{r,2,5, Appearance-> "Labeled"}]