# Thread: Coordinate Geometry Proofs

1. ## Coordinate Geometry Proofs

Given:
A(–2,2), B(6,5), C(4,0), D(–4,–3)

Prove:
ABCD is a parallelogram but not a rectangle.

2. Originally Posted by magentarita
Given:
A(–2,2), B(6,5), C(4,0), D(–4,–3)

Prove:
ABCD is a parallelogram but not a rectangle.
ABCD is a parallelogram --->
1. lengths AB=CD
2. lengths AD=BC

Or in terms of vectors :
$\overrightarrow{AB}=\overrightarrow{DC}$

A sketch can make you understand why I chose these letters.

3. ## Good tip...

Originally Posted by Moo
ABCD is a parallelogram --->
1. lengths AB=CD
2. lengths AD=BC

Or in terms of vectors :
$\overrightarrow{AB}=\overrightarrow{DC}$

A sketch can make you understand why I chose these letters.
Thanks for the tip.