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We began class by revisiting Proposition 2.21, part 3. Last time we were unable to come up with

a contradiction to our assumption that points B and E are on opposite sides of . After some

discussion of how to go about this, and whether or not we should think about it some more and

discuss it at another point, Emina completed the proof.Proposition 2.21- If D is in the interior of

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different meanings in different contexts. Therefore, it is okay that we have a definition of

congruent because our definition is in relation to congruent triangles.

Emina talked about congruent triangles on the whiteboard and what exactly we meant by

congruent triangles. implies that , , ,

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