SOLUTION: Hello, I am a 10th grade and I really need help with this proof please. The question is triangle ACB. At point C, two lines are drawn. Point D and E. Which go on the same line of A

Algebra ->  Geometry-proofs -> SOLUTION: Hello, I am a 10th grade and I really need help with this proof please. The question is triangle ACB. At point C, two lines are drawn. Point D and E. Which go on the same line of A      Log On


   

Question 174950: Hello, I am a 10th grade and I really need help with this proof please. The question is triangle ACB. At point C, two lines are drawn. Point D and E. Which go on the same line of A and B, so points D and E are in between those two corners/points. I was just describing it, thats not the question.
The Given: angle CDE is congruent to angle CED, line AD is congruent to line EB.
I need to prove that angle ACD is congruent to angle BCE.
So far I drew that angle CDE is congruent to angle CED. I marked the triangle. and that AD is congruent to EB. I dont know where to start. Please help me.

Answer by Mathtut(3670) About Me  (Show Source):
You can put this solution on YOUR website!

***************************************************************************
               statement                    reason
***************************************************************************

1.angle CDE congruent to angle CED       1.Givens
  AD congruent to EB

2.CDA + CDE = 180                        2.Partition postulate
  CEB + CED = 180

3.CDA+CDE = CEB+CED                      3.transitive prop.

4.CDE+CDE = CEB+CDE                      4.substition prop(CDE congruent CED)

5.CDE congruent CBE                      5.subtraction prop.

6.CD congruent to CE                     6.corresponding sides and angles of 
                                           isosceles triangle are congruent

7.tri ACD congruent tri BCE              7.SAS

8.ACD congruent BCE                      8. CPCTC

partition post.-the whole is equal to the sum of the parts.
:
SAS- If two sides and the included angle of one triangle ar congruent
to the correspoinding parts of another triangle then triangles are congruent
:
CPCTC- Corresponding parts of congruent triangles are congruent