Part I: Angle Sum Relationships
Arrange the three congruent triangles so that angles 1 and 3 are adjacent to one another, and angle 2 is adjacent to angles 1 and 3.

B. What do you notice about the three angles?

C. What do they appear to form?

D. What can you conclude about the sum of the angles in a triangle?

Part I Angle Sum Relationships Arrange the three congruent triangles so that angles 1 and 3 are adjacent to one another and angle 2 is adjacent to angles 1 and class=