Proving Quadrilaterals are Parallelograms

In this lesson I will teach you how to prove a quadrilateral is a parallelogram.  Of course not every quadrilateral is a parallelogram so it’s important for you to know how to identify and prove a quadrilateral is in fact a parallelogram.  Now, why would you care if a quadrilateral is or is not a parallelogram?  Well, one good reason is that once we know a figure is in fact a parallelogram we know a lot about it’s properties and features- this information can really help use solve problems.  Hence, you want to know methods of proving  a quadrilateral is a parallelogram and that’s our focus in this lesson.  As you will see in the video, we will be using lots of theorems to prove a quadrilateral is a parallelogram.  The basic idea is you will look at a quadrilateral and see if it matches the properties of a parallelogram- if it does than you can prove the quadrilateral to be a parallelogram.  Don’t forget the previous lessons on how to plan and write a proof as it will help you a lot with this topic.  Finally, take great notes and keep reviewing course material as the concepts build on each other.