CalculatorUser

Of course its a parrelelogram, but is it in the order ABCD?
 

Because your correspondences dont seem to make sense.

It is supposed to go in alphabetical order like the image above.

Look at your proof, then look at the image above, does it make sense?

Is this theorem given?

" _{opposite pair of sides are parallel lines and diagonals are not perpendicular "}

I am kind of confused, for your proof, is it based on parellelogram ABCD?

If it is based on ABCD, you have to check the corresponding segments.

Also, \(|\overline{CB}|\neq|\overline{DA}|\) is incorrect I think. Because that is saying that they are not equal in LENGTH. You want to prove that they are NOT perpendicular.

So you have to do this I think. \(|\overline{CB}|\not\perp|\overline{DA}|\)

That is my new search engine now

Yes it is and see Tomson's link

ok I assumed I helped! 

Me too!
I make many!
 

These are the two out of (dozens?) mistakes I made

oops! At least you know what NOT to do.

Also, I think the Absolute value means that the length or magnitude is positive, because segments can't be negative.

I know less than you lol. I am researching as I post this.

There are actually multiple ways to prove it, do you HAVE to use your theorem (1)?

Prove that both pairs of opposite sides are parallel.

Prove that both pairs of opposite sides are congruent.

Prove that one pair of opposite sides is both congruent and parallel.

Prove that the diagonals bisect each other.

Also, are you sure Diagonals can't be perpendicular? Because perpendicular diagonals form squares, and squares are parrellelograms.

Wha types of proofs are you doing?

Statement Reason?