An equilateral triangle has 3 sides of equal length. ... The interior angle and its corresponding exterior angle always add up to 180°. The sum of interior angles in a triangle.

So equilateral triangles are constructible with a compass and straightedge, QED. Congratulations on persisting through the first proposition in the first book of Euclid’s Elements . Only 13 more ...

L'Enfant's design endures in modern D.C., where wide avenues cut angles across the city's grid. ... and found herself particularly drawn to the equilateral triangles that took shape in his designs.

"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 ...

An equilateral triangle has 3 sides of equal length. ... The interior angle and its corresponding exterior angle always add up to 180°. The sum of interior angles in a triangle.