Applying Angle Relationships
You'll often need to identify angle relationships from diagrams. Look for characteristic positions: vertical angles appear across from each other at intersections, adjacent angles share a side and vertex, and linear pairs form straight lines.
When solving problems with complementary or supplementary angles, create an equation based on their sum. For complementary angles, A+B=90°. For supplementary angles, A+B=180°. For example, if angle A is 42° and angles A and B are complementary, then 42°+B=90°, making angle B equal to 48°.
More complex problems involve algebraic expressions. If two supplementary angles have a relationship like "one angle is twelve less than twice the other," you can write this as A=2B-12, then substitute into A+B=180° to solve for both angles.
🔍 When working with angle ratios, convert the ratio to variables first. For example, if complementary angles have a ratio of 1:2, call them x and 2x, then solve x+2x=90° to find x=30° and 2x=60°.