The reason the shape changes from 3D to 2D when you get to six triangles has to do with the number of degrees in an equilateral triangle. There are 60 degrees at each vertex of the triangle, so ...

An equilateral triangle, as we’ve already learned, is a "perfect" triangle with 90-degree angles on each corner. All sides are exactly the same length.

"The triangle in the northwest Valley was probably Luke Air Force Base Auxiliary Field 1. That is part of an old airfield that is now used for instrument training by F-16 pilots. There was another ...

Henry Dudeney, a self-taught English mathematician and puzzle columnist, asked his readers to dissect an equilateral triangle into the smallest number of pieces that could be rearranged into a square.

Thalhammer was fond of L'Enfant's use of stars and triangles in his plan for the city – and found herself particularly drawn to the equilateral triangles that took shape in his designs.