Cupola (geometry): Geometry, Polygon, Equilateral Triangle

Equilateral Triangle: Geometry, Triangle (geometry), Euclidean Equiangular Polygon

Equilateral Polygon: Geometry, Polygon, Triangle, Internal Angle

Equiangular Polygon: Euclidean Geometry, Polygon, Regular Equilateral Triangle

Morley's Trisector Theorem: Plane Geometry, Triangle, Equilateral Triangle