Writing a proof

Write a two column proof for one of  following. Remember, the left hand column is statements and the right hand column is reasons.  Make sure the steps are in a logical order.  Before you start, make sure you draw and label a diagram and try to "prove" it before you write your proof.   Start with the givens, put any postulates, definitions, etc.. that might apply, have the "prove" as a goal.  Remember, this is a learning experience! Take your time and do the best you can. 

Last name starts with A-L? Do this one!
Given= C is on segment on DE, DC=x, CE=3X, and DE=16.
Prove:x=4.


Challenge: What additional statements/reasons would you add on to prove 12=CE?

Last name starts with M-Z? Do this one!
Given B is in the interior of <CAR, m<CAB=x, m<BAR=6x, and m<CAR=91.
Prove: x=13.

Challenge: What additional statements/reasons would you add on to prove that 78=m<BAR?

Welcome to our Geometry Blog!

We will be blogging in Geometry this year.  This is a great way to use technology and good way to exchange ideas, problem-solve, etc... 

For your first post,  please let me know what you like most about geometry.  Also, give me an idea of what I can do to help you have a successful  year in geometry.