Classifying Angle Pairs
Classifying angle pairs is a Grade 7 geometry skill in Big Ideas Math Advanced 2, Chapter 12: Constructions and Scale Drawings. Two angles are complementary if their measures sum to 90 degrees, supplementary if they sum to 180 degrees, and neither if their sum is any other value. For example, 35 degrees and 55 degrees are complementary because 35 plus 55 equals 90.
Key Concepts
To classify angle pairs: Add the measures and compare to $90°$ and $180°$. Complementary: $\text{angle} 1 + \text{angle} 2 = 90°$ Supplementary: $\text{angle} 1 + \text{angle} 2 = 180°$ Neither: sum is not $90°$ or $180°$.
Common Questions
What is the difference between complementary and supplementary angles?
Complementary angles sum to 90 degrees, while supplementary angles sum to 180 degrees. For example, 35 and 55 degrees are complementary, while 120 and 60 degrees are supplementary.
How do you classify a pair of angles?
Add the measures of both angles. If the sum equals 90 degrees, they are complementary. If the sum equals 180 degrees, they are supplementary. If neither, they have no special classification.
What are examples of complementary angles?
Any two angles whose measures add up to exactly 90 degrees are complementary. For example, 30 and 60, 45 and 45, or 20 and 70 degrees are all complementary angle pairs.
What textbook covers classifying angle pairs in Grade 7?
Big Ideas Math Advanced 2, Chapter 12: Constructions and Scale Drawings covers complementary, supplementary, and other angle pair classifications.