Jeremy and arnold were talking about the lesson that they had covered recently in math class. mrs. hudson, their math teacher, always encouraged the boy to "see the math for themselves," meaning she wanted the boys simply not to accept what they've been taught, but to really prove the ideas to themselves. they covered several topics recently that they were struggling with how to prove the concepts were true. cut apart and use the diagrams of the three triangles attached to the last page to establish relationships and the boys better understand the concepts. 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