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In an isosceles triangle, the two angles opposite the congruent sides are called the base angles. You may have learned in a previous course that the base angles of an isosceles triangle are always congruent. Now you will prove it! In the diagram at right, is an isosceles triangle, and point is the midpoint of . Homework Help ✎

  1. ​Make a flowchart to prove that the base angles of are congruent, that is, prove that .

  2. Would your proof work for any isosceles triangle? State your findings as an if-then statement and add it to your Theorem Graphic Organizer.

    Since we found this to be true, formulate an if-then statement to conclude information from the flowchart.