Extended side Pentagon Angle Sum

thingiverse

A geometric puzzle tray features five triangles arranged in a pentagonal shape with each triangle laid off at right angles. If a side of the design is extended, two clear right angles become visible. By placing the smallest angles (18 degrees) of each triangle into the exterior angle created by extending the wall, it becomes evident that the sum of the five triangles' smallest angles equals one complete right angle. This innovative concept was conceived and crafted by myself, not copied from anyone else. Although I drew inspiration from a geometry homework problem assigned by Dan Jackson's class, I did prove this idea independently. The original problem required students to demonstrate that if each wall of the pentagon is extended in the same direction, the resulting five exterior angles total four right angles. I'm grateful for your attention and hope you found this concept engaging as well as instructive.