A Right Angle Theorem - Lesson 4.3
We started today with the following warmup problem...you should be able to come up with a diagram, the "given" and "prove" statements and the proof!! The problem was to "Prove that the median to the base of an isosceles triangle is an altitude to the base."
In the following proof, we have to prove that two angles that are both supplementary and congruent are right angles. This is a new theorem, whose proof is shown below...it should be pretty intuitive.
Next, we went over an example of how this theorem might be used in a
proof...there are many other examples in the homework for this