documentclass[tikz]{standalone}
usetikzlibrary{shapes}
begin{document}
begin{tikzpicture}[>=latex,shorten >=2pt,shorten <=2pt,shape aspect=1]
node (A) [cylinder, shape border rotate=90, draw,minimum height=3cm,minimum width=2cm]
{A};
draw [<->] (A.before top) -- (A.after top) node [midway, above,fill=white] {$A_0$};
end{tikzpicture}
end{document}

begin{tikzpicture}[join=round]
    tikzstyle{conefill} = [fill=blue!20,fill opacity=0.8]
    tikzstyle{ann} = [fill=white,font=footnotesize,inner sep=1pt]
     tikzstyle{ghostfill} = [fill=white]
     tikzstyle{ghostdraw} = [draw=black!50]
filldraw[conefill](-.775,1.922)--(-1.162,.283)--(-.274,.5)
                    --(-.183,2.067)--cycle;
filldraw[conefill](-.183,2.067)--(-.274,.5)--(.775,.424)
                    --(.516,2.016)--cycle;
filldraw[conefill](.516,2.016)--(.775,.424)--(1.369,.1)
                    --(.913,1.8)--cycle;
filldraw[conefill](-.913,1.667)--(-1.369,-.1)--(-1.162,.283)
                    --(-.775,1.922)--cycle;
draw(1.461,.107)--(1.734,.127);
draw[arrows=<->](1.643,1.853)--(1.643,.12);
filldraw[conefill](.913,1.8)--(1.369,.1)--(1.162,-.283)
                    --(.775,1.545)--cycle;
draw[arrows=->,line width=.4pt](.274,-.5)--(0,0)--(0,2.86);
draw[arrows=-,line width=.4pt](0,0)--(-1.369,-.1);
draw[arrows=->,line width=.4pt](-1.369,-.1)--(-2.1,-.153);
filldraw[conefill](-.516,1.45)--(-.775,-.424)--(-1.369,-.1)
                    --(-.913,1.667)--cycle;
draw(-1.369,.073)--(-1.369,2.76);
draw(1.004,1.807)--(1.734,1.86);
filldraw[conefill](.775,1.545)--(1.162,-.283)--(.274,-.5)
                    --(.183,1.4)--cycle;
draw[arrows=<->](0,2.34)--(-.913,2.273);
draw(-.913,1.84)--(-.913,2.447);
draw[arrows=<->](0,2.687)--(-1.369,2.587);
filldraw[conefill](.183,1.4)--(.274,-.5)--(-.775,-.424)
                    --(-.516,1.45)--cycle;
draw[arrows=<-,line width=.4pt](.42,-.767)--(.274,-.5);
node[ann] at (-.456,2.307) {$r_0$};
node[ann] at (-.685,2.637) {$r_1$};
node[ann] at (1.643,.987) {$h$};
path (.42,-.767) node[below] {$x$}
    (0,2.86) node[above] {$y$}
    (-2.1,-.153) node[left] {$z$};
end{tikzpicture}