standard_description: 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.
problem_activity: Determine if the statement below is always, sometimes, or never true. Explain your reasoning.
“To prove two triangles similar, you need to prove that two of the corresponding sides are proportional.”


aligns: no