Adjacent Angle Relationships
Adjacent Angle Relationships is a Grade 7 math topic in Big Ideas Math Advanced 2, Chapter 12: Constructions and Scale Drawings. Students learn that adjacent angles forming a right angle are complementary (sum = 90 degrees) and adjacent angles forming a straight line are supplementary (sum = 180 degrees). This concept helps identify angle pair relationships in geometric diagrams.
Key Concepts
Adjacent angles that form a right angle are complementary: $\angle A + \angle B = 90°$.
Adjacent angles that form a straight line are supplementary: $\angle A + \angle B = 180°$.
Common Questions
What are adjacent angles?
Adjacent angles are two angles that share a common vertex and a common side. They lie next to each other without overlapping.
When are adjacent angles complementary?
Adjacent angles are complementary when they form a right angle together, meaning their measures add up to 90 degrees. For example, 35 degrees and 55 degrees are complementary adjacent angles.
When are adjacent angles supplementary?
Adjacent angles are supplementary when they form a straight line together, meaning their measures add up to 180 degrees. For example, 120 degrees and 60 degrees are supplementary adjacent angles.
If two adjacent angles form a right angle and one measures 42 degrees, what is the other?
The other angle measures 90 - 42 = 48 degrees, since complementary angles sum to 90 degrees.