Honors Geometry Unit 5 Notes

Proofs

• the sum of the measures of the interior angles of a triangle is $180^{\circ}$
• the base angles of isosceles triangles are congruent
• the segment joining the midpoints of two sides of a triangle is parallel to the third side and half the length
• a line parallel to one side of a triangle divides the other two proportionally, and conversely
• the Pythagorean Theorem using triangle similarity.