Applying the Properties of a Parallelogram

In this video, you will learn the six important properties of parallelograms and how to apply them. A parallelogram is a quadrilateral with both pairs of opposite sides parallel. Remember, a quadrilateral is a four-sided figure. Click the player button to begin.
View a transcript of this video.
Applying the Properties of a Parallelogram
Given: Parallelogram HJKL
What is the measure of angle HKL?
Read below to learn one strategy to find the unknown angle measure.
Step 1: Focus on Triangle HJK.
The sum of the measures of the angles of a triangle equals 180°. Therefore, the measure of angle JHK equals 30°.
Step 2: Focus on alternate interior angles.
The opposite sides of a parallelogram are parallel. Recall that if parallel lines are intersected by a transversal, then the alternate interior angles are congruent. So, the measure of angle JHK is equal to the measure of angle HKL. Therefore, the measure of angle HKL equals 30°.
Parallelograms Review

Now that you have learned about parallelograms, review your knowledge in this interactivity. Click the player button to get started.