1997 USAMO Problems/Problem 4
Problem
To clip a convex -gon means to choose a pair of consecutive sides
and to replace them by three segments
and
where
is the midpoint of
and
is the midpoint of
. In other words, one cuts off the triangle
to obtain a convex
-gon. A regular hexagon
of area
is clipped to obtain a heptagon
. Then
is clipped (in one of the seven possible ways) to obtain an octagon
, and so on. Prove that no matter how the clippings are done, the area of
is greater than
, for all
.