CK12 - Geometry

Imaginethat you are tryingto find the relationshipbetween and. To help you understand

the relationship,extendall of the segmentsinvolvedwith theseanglesand remove.

Whatyou shouldnoticeis that and are two parallellinescut by transversal. So, you can
find the relationshipsbetweenthe anglesas you learnedin Chapter1. Earlierin this course,you learned

that in this scenario,two consecutiveinterioranglesare supplementary;they sum to. The sameis
true withinthe parallelogram.Any two consecutiveanglesinsidea parallelogramare supplementary.

Example 3

Fill in the remainingvaluesfor the anglesin parallelogram below.

You alreadyknowthat sinceit is givenin the diagram.Sinceoppositeanglesare con-

gruent,you can concludethat.

Now that you knowthat consecutiveanglesare supplementary, you can find the measuresof the remaining

anglesby subtracting from.