Thurs 8/19/10

HW: HANDOUT from class with 3 problems that require a nice paragraph proof. Sit and think about the statements you need to prove. Reread the proof of the midpoint theorem closely observe the flow and logical reasoning of its statements.

NOTE: for proofs #2 and #3, you can use the other midpoint theorem conclusion that says " if M is the midpoint of segment AB, then AM = 1/2AB and MB = 1/2AB".

Hi,

Today we talked about and proved the MIDPOINT THEOREM (still in section 1-5). We will start the practice of geometric proofs by writing them in the "paragraph form". Later in the sections, they will be written in 2-columns with numbered statements and reasons.

Please know that we prove statements in math because it is important to show how and why they are TRUE. No one wants to study false "things" in depth. There is no point to that.

Some of you found the proof of the midpoint theorem redundant... this might be because it was easy and/or the conclusion of the midpoint theorem is obvious.

Remember that we use given information, definitions, postulates, and previously proven theorems to prove other theorems. Notice that we used the given information (that M is the midpoint of...) and 2 definitions (for midpoint and congruence) to prove the Midpoint Theorem.