##
Ken's Puzzle of the Week

A Hidden Hexagon

In the figure, triangles ABC, DEF, and GHJ are congruent isosceles triangles.
Angles B and C are 80 degrees. Points AEFC, EHJD, DFB, and GHF are
collinear. Without drawing a circle, show how to mark the corners of a perfect hexagon
on the diagram, using only a
compass set to a constant length. Prove it's a perfect hexagon.

Source: Original. (Original Visio of
graphic.)

Solution

Mail to Ken