A triangle is a polygon. It is a closed 3-sided shape made up of straight lines. The ‘tri-’ part of the word triangle means three. A triangle has 3 sides and 3 angles. Interior angles are the angles ...

Named for Plato, who theorized that the classical elements were made of these regular polyhedrons, three of the Platonic solids are composed of equilateral triangles: the tetrahedron, octahedron, and ...

👉 Learn how to find the missing side of a triangle. A triangle is a polygon with three sides. Triangles are classified on the basis of the angles or on the basis of the sides. The classification of a ...

👉 Learn how to classify triangles. A triangle is a polygon with three sides. Triangles are classified on the basis of its ...