unitsize(1cm);
import solids;
import math;

currentprojection=orthographic(0,100,25);

real r=4, h=7;
triple pO=(0,0,0);
triple pOprime=(0,0,3);
triple pS=(0,0,h);
triple pA=(r,0,0);
revolution rC=cone(pO,r,h,Z);

rC.draw();

skeleton s;
real tOprime=abs(pOprime)/h;
rC.transverse(s,reltime(rC.g,tOprime));
triple pAprime=relpoint(pA--pS,tOprime);
rC.longitudinal(s);
draw(s.back,dashed);
draw(s.front);

label("$S$",pS,N);
dot(Label("$O$",align=SE),pO);
dot(Label("$O'$",align=SE),pOprime);
dot(Label("$A$",align=W),pA);
dot(Label("$A'$",align=W),pAprime);

draw(pS--pO^^pO--pA^^pOprime--pAprime,dashed);