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 ...

The sum of the angles inside any polygon can be found by spitting the polygon into triangles. Sum of interior angles = 180(n – 2) where n is the number of sides In a regular polygon all the angles are ...