A pyramid with a triangular base is a triangle-based pyramid. A tetrahedron is a triangular pyramid with all equilateral triangle faces. A pyramid with a square base is a square-based pyramid.

The fire extinguisher class explains the classic fire triangle or tetrahedron, common-sense responses to fire scenarios, the use and capabilities of the different kinds of extinguishers, and hands-on ...

The Tetrahedron Constellation Gravitational Wave Observatory ... Backers of the conceptual plan say TEGO offers significant advantages over designs consisting of a triangular configuration of three ...