In this video lesson, students see that angles do not need to be adjacent to be complementary or supplementary. Students are also introduced to and begin to use the term vertical angles for describing the opposite angles formed when two lines cross. They examine multiple examples and see that the vertical angles have equal measures. Students can relate this understanding to the fact that both angles in a pair of vertical angles are supplementary to the same angle in between. By the end of the lesson, students will be able to see the different ways of making pairs of supplementary angles in two crossing lines.
In this video lesson, students are introduced to the terms complementary, for describing two angles whose measures add to 90°, and supplementary, for describing two angles whose measures add to 180°. They practice finding an unknown angle given the measure of another angle that is complementary or supplementary. Students realize that many angles share the same vertex as other angles, so they must be precise when naming each angle (MP6) in addition to describing the relationship between pairs of angles.
Grade 7, Episode 22: Unit 7, Lesson 2 | Illustrative Math
You'll learn how to prove that every trapezoid has two pairs of supplementary angles with this interactive video from the School Yourself Geometry series.
