Susanna Post, the 2021 Arkansas Teacher of the Year, is getting ready for a model sailboat race. Her sailboat has triangular-shaped sails. Can you help her name and classify triangles? Rise and Shine ...

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 classification of shapes in middle and high school geometry often seems very mysterious to students, featuring strange terms such as isosceles, trapezoids, and kites, which are defined by a ...