In this Grade 7 lesson from Big Ideas Math, Course 2, students learn to classify pairs of angles as complementary (summing to 90°) or supplementary (summing to 180°). Students also practice finding unknown angle measures by setting up and solving equations using these angle relationships. The lesson aligns with Florida standard MAFS.7.G.2.5 within the Chapter 7 unit on Constructions and Scale Drawings.
Section 1
Definitions of Complementary and Supplementary Angles
If the sum of the measures of two angles is 180°, then the angles are supplementary.
If the sum of the measures of two angles is 90°, then the angles are complementary.
Section 2
Finding Unknown Angle Measures
To find unknown angle measures in complementary and supplementary pairs:
Set up an equation using the given information and solve for the unknown variable.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter
Expand to review the lesson summary and core properties.
Section 1
Definitions of Complementary and Supplementary Angles
If the sum of the measures of two angles is 180°, then the angles are supplementary.
If the sum of the measures of two angles is 90°, then the angles are complementary.
Section 2
Finding Unknown Angle Measures
To find unknown angle measures in complementary and supplementary pairs:
Set up an equation using the given information and solve for the unknown variable.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter