November 17–November 23, 2009

Problem

Suppose that we have a parallelogram with area 1. Draw lines from each corner to a points 1/3 of the way along the opposite sides, as shown below. What is the area of the octagon in the middle?

parallogram with an octagon inside

Solution

here

List of solvers

David Lingenbrink (high school), Arthur J. Anende (graduate), Congpa You, Lloyd Sakazaki, Greg Rudzinski, Eric Brodeur, Qiyuan Wei, Jens Malmquist, Mukund Tirumalai (outside).

Arthur Anende wins the prize!