Students will be able to define a triangle.
Triangle is a convex polygon with three segments joining three non-collinear points.
Each of the three segments is called a side, and each of the three non-collinear points is called a vertex. Triangles can be categorized by the number of congruent sides they have. Triangles can also be categorized by their angles. In addition, the exterior angle of a triangle is the supplement of the adjacent interior angle. The measure of the exterior angle is also the sum of the measures of the two remote interior angles.