Prove theorems about parallelograms. Theorems include: opposite sides are congruent, opposite angles are congruent, the diagonals of a parallelogram bisect each other, and conversely, rectangles are parallelograms with congruent diagonals.

How Do You Find Values for Variables in the Angles of a Quadrilateral To Make it a Parallelogram?

When you're given a quadrilateral with some of the interior angles defined with variables, you can find what values those variables need to have to make that quadrilateral a parallelogram. Follow along with this tutorial to learn what steps to take to get the answer!
How Do You Use the Diagonals of a Rectangle to Find the Value of a Variable?

When you make diagonals inside a rectangle, those diagonals are congruent. With this information, you can find the value of a variable that's part of a measurement of a diagonal. This tutorial shows you the steps.
How Do You Find the Value for a Variable in the Angles of a Quadrilateral To Make it a Rhombus?

A parallelogram needs to have certain qualities in order to be a rhombus. In this tutorial, you'll use your knowledge of these shapes in order to find the value for a variable that will make a given parallelogram a rhombus.
What is a Parallelogram?

A parallelogram is a special type of quadrilateral with some special properties. In this tutorial, take a look at parallelograms and learn what kinds of quadrilaterals can also be called parallelograms!