Tests for Parallelograms How do you know/determine if a quadrilateral can be called a parallelogram??

What do you look for? There are 6 “tests”. If a quadrilateral can pass any ONE of the six tests, then it is a parallelogram. Do not assume any information unless you have specific markings, lengths, or degree measures given.

Test #1: Are both pairs of opposite sides parallel? Markings-arrows on the sides indicate if you have parallel sides. No arrows? Don’t assume. This quadrilateral has opposite sides marked with arrows, so it is a parallelogram.

Test #2: Are both pairs of opposite sides congruent? Look for actual numbers that show the lengths of sides, or look for the tick marks that mean sides are congruent. Since opposite sides are marked congruent in the first figure, and opposite sides have the same lengths in the second figure, they are both parallelograms. 8 10

Test #3 Are both pairs of opposite angles congruent? Look for markings at the angles or actual degree measures to see if this is true. In the first figure, opposite angles are marked with arcs to show they are congruent. In the second figure, opposite angles have the same degree measure. Both quadrilaterals are parallelograms. 120° 60°

Test #4 Do the diagonals bisect each other? Look for the tick marks to show that diagonals have been split into two congruent parts. Look for numbers that show the diagonals have two equal parts. 8 5

Test #5 Are same-side angles supplementary? Check to see if the given angles add to 180 degrees.

Test #6: Is ONE pair of opposite sides BOTH congruent and parallel? You only need markings on one pair of sides, but it MUST have both arrows and tick marks, or arrows and side lengths given.

You try it… Answer the “Am I a Parallelogram” questions on the worksheet given to you. Be sure to write down which test the quadrilateral “passed” if it is a parallelogram, or “failed” if it isn’t a parallelogram