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