After having studied multiple books on geometry, I found it frustrating that these books (MGMAT, Veritas
) do a poor job of explaining properties of important figures such as the parallelogram.
For GMAT, you need to understand what is sufficient to make a figure a parallelogram. This is especially true for the DS. It is also important to know what implications you get from a figure that is parallelogram. Neither of the books explained these points in details.
So, I made a summary of parallelogram properties and attached it here. Hope this helps others who find geometry a challenge.
Please note: the problems are imaginary, and simplified. They are written to give you an idea of application of the property knowledge on the GMAT.
I appreciate any constructive feedback, to further improve the material.
If you like my post, a kudos is not expected but appreciated