code for cone diagram

> circ:=plot([cos(t),sin(t),t=0..2*Pi],linestyle=3,
thickness=1):

> tri:=plots[polygonplot]([[-1,0],[cos(Pi/6),sin(Pi/6)],
[cos(-Pi/6),sin(-Pi/6)]],thickness=2):
txt:=plots[textplot]([cos(Pi/6)+.25,sin(Pi/6)+.25,
`( h-R, r)`],font=[TIMES,BOLD,18]):
pt:=plottools[disk]([cos(Pi/6.),sin(Pi/6.)],
.02,color=black):

> plots[display]({circ,tri,txt,pt},scaling=constrained,
xtickmarks=[],ytickmarks=[]);