Deepen your understanding of angle relationships — complementary, supplementary, and angles formed by intersecting lines.
Two angles are complementary if they add up to 90°. Two angles are supplementary if they add up to 180°.
Find the complement of 35°.
90° − 35° = 55°
Find the supplement of 110°.
180° − 110° = 70°
When two lines cross, they form vertically opposite angles, which are always equal. Adjacent angles on a straight line add up to 180° (a linear pair).
Two lines intersect, forming an angle of 65° on one side. What is the vertically opposite angle?
65°, since vertically opposite angles are equal
Two adjacent angles on a straight line are in the ratio 2:3. Find both angles.
Total = 180°, so parts = 5, one part = 36°; angles are 72° and 108°
1. Find the complement of 62°.
2. Find the supplement of 75°.
3. Two lines intersect, forming a 48° angle. What is the vertically opposite angle?
4. Two adjacent angles on a straight line are in the ratio 1:2. Find both angles.
5. Two angles are complementary, and one is 3 times the other. Find both angles.