1. 1-5 Angle Relations

2. Special Angle Pairs

3. Pairs of Angles
Some pairs of angles are special because of how they are positioned in relationship to each other. Three of these angle pairs are described below.

4. Adjacent angles
ADJACENT ANGLES are two angles that lie in the same plane and have a common vertex and a common side, but no common interior points
EXAMPLE

5. Linear Pair
A LINEAR PAIR is a pair of adjacent angles with non-common sides that are opposite rays.

6. Vertical Angles
VERTICAL ANGLES are two non adjacent angles formed by two intersecting lines.

7. Angle Pair Relationships

8. Complementary Angles
Complementary Angles are two angles with measures that have a sum of 90 degrees

9. Supplementary Angles
Supplementary angles are two angles that have a sum of 180 degrees.

10. The angles in a linear pair are supplementary

11. Acute Angles
An angle of fewer than 90 degrees

12. Obtuse angles
An angle greater than 90 degrees

13. Perpendicular lines
Lines, segments, or rays that form right angles are PERPENDICULAR
Perpendicular lines intersect to form four right angles
Perpendicular lines intersect to form congruent adjacent angles
Segments and rays can be perpendicular to lines or other line segments and rays

14. Perpendicular Lines

15. Exercise What is another name for l? Name the intersection of l and m?
Name three collinear points.

16. Algebra
Angle E and Angle F are supplementary. The measure of Angle E is 54 more than the measure of Angle F. Find the measures of each angle.

17. Algebra
The measure of an angle’s supplement is 76 less than the measure of the angle. Find the measure of the angle and its supplement.

18. Algebra
The measure of the supplement of an angle is 40 more than two times the measure of the complement of the angle.

19. Algebra
Angle 3 and Angle 4 form a linear pair. The measure of Angle 3 is four more than three times the measure of Angle 4. Find the measure of each angle.