1. Simple math proof help?

Given: m <2 = m <4

Prove: m <1 = m <3

2. Re: Simple math proof help?

Originally Posted by Connorzman
Given: m <2 = m <4
Prove: m <1 = m <3
From the given you know that $\overline{AB}\parallel\overline{DC}$

3. Re: Simple math proof help?

Originally Posted by Plato
From the given you know that $\overline{AB}\parallel\overline{DC}$
It certainly looks like AB and DC are parallel, but I think it is more logical to use the angles directly. Angles AEB and DEC are vertex angles so they are equal. Since we are given that angles 2 and 4 are equal we may say that the angles 1 and 3 are equal since the sum of interior angles of a triangle is 180 degrees. ie. 180 = angle 2 + angle AEB and 180 = angle 4 + angle DEC. Can you finish this up?

-Dan

4. Re: Simple math proof help?

Originally Posted by topsquark
It certainly looks like AB and DC are parallel, but I think it is more logical to use the angles directly. Angles AEB and DEC are vertex angles so they are equal. Since we are given that angles 2 and 4 are equal we may say that the angles 1 and 3 are equal since the sum of interior angles of a triangle is 180 degrees. ie. 180 = angle 2 + angle AEB and 180 = angle 4 + angle DEC. Can you finish this up?
There are parallel by the alternate interior theorem.