SOLUTION: Given: Parallelogram ABCD Use a two column proof to prove that angle B and angle D are congruent. I don't know if it matters, but the points are in this order: A D B C

Algebra ->  Parallelograms -> SOLUTION: Given: Parallelogram ABCD Use a two column proof to prove that angle B and angle D are congruent. I don't know if it matters, but the points are in this order: A D B C       Log On


   

Question 1116487: Given: Parallelogram ABCD
Use a two column proof to prove that angle B and angle D are congruent.
I don't know if it matters, but the points are in this order:
A D
B C
Thanks!

Answer by Alex.33(110) About Me  (Show Source):
You can put this solution on YOUR website!
since AD is parallel to BC, angle A + angle B = 180 deg; (identity of Parallelograms)
since AB is parallel to CD, angle A + angle D = 180 deg; (identity of Parallelograms)
Thus, angle B and D are congruent. (obvious deduction; conclusion of the proof)

THE CONTENT OF THE SECOND COLUMN ARE WRITTEN IN PARENTHESES. SORRY FOR NOT BEING ABLE TO PRINT CHARTS ON THIS SITE)
Plus, the order of endpoints does not matter, because expression 'Parallelogram ABCD' indicates that when counting endpoints in clockwise or counterclockwise direction you get A-B-C-D(OR REVERSE) instead of A-C-B-D. A must be next to B, B next to C, C next to D, etc.