Section 4-2

Section 4-2
Vocab: Corollary- An addition to a theorem, that is easily proved using that theorem
Theorems:

• Triangle Sum Theorem(4.1) The sum of the measures of the interior angles of a triangle is 180
  

• Theorem (4.2) -There can be at most one right angle or one obtuse angle in any given triangle. The other 2 angles are always acute
• Exterior Angle Theorem- The measure of an exterior angle of a triangle is equal to the sum of the measures of the opposite 2 nonadjacent angles (remote interior angles)
• Third Angle Theorem- If 2 of the one triangle are congruent to another triangle, the third angles must also be congruent.

Flow Proof:
Examples from class: