Prove theorems about triangles. Theorems include: measures of interior angles of a triangle sum to 180?; base angles of isosceles triangles are congruent; the segment joining midpoints of two sides of a triangle is parallel to the third side and half the length; the medians of a triangle meet at a point.
Exercises from Illustrative Mathematics A set of exercises, commentary, and solutions. For this unit, choose:
G-CO Midpoints of Triangle Sides G-CO Congruent angles in isosceles triangles G-CO Sum of angles in a triangle