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The Case of the Missing Diagram - Lesson 4-2

Today, we talked about how to set up proofs for which you are not given a diagram or the "given" and "prove" statements.  You should be able to do these, so make sure you follow the logic here.  We started with the following problem:

Example 1 Question

Now...don't freak!  Think about what we know from the statement and what we need to prove.  We know that two altitudes of a triangle are congruent, right?  So, that means we have a triangle and two of its altitudes in our diagram.  We also know that the altitudes are congruent.  From this, you should be able to show the following:

Example 1 Given and Diagram

Now all we need is the "prove" statement.  It's what comes after the "then" in the original statement:  "the triangle is isosceles."

Example 1 Answer

We then went over a few more should be able to follow these and the ones we had for homework!!  If you don't, then ask a friend, come see me, or study them until you do.  There will be one of these on the test!!!

Example 2


Example 3


You should be able to do the proofs for these as fact, they should be getting easier for you.

Other Links
Class Notes
Lesson 4-1
Lesson 4-2
Lesson 4-3
Lesson 4-4
Lesson 4-5
Lesson 4-6
Test Topics
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