1. Angle Relationships

2. Adjacent Angles • Adjacent Angles • Are “next to” each other • Share a common side C D J are adjacent K are not adjacent - they do not share a side

3. Vertical Angles Vertical Angles • Are across from each other when two lines intersect • Are Congruent There are two pairs of vertical angles: 1 2 4 3 What appears to be true about these two pairs of angles? We show that by using “tick marks” over the arcs

4. Complementary Angles Complementary Angles -Two angles whose sum is 90° A B are complementary Angles M and N are complementary. If the measure of is 37°, what is m ? M N is 53°

5. Supplementary Angles Supplementary Angles -Two angles whose sum is 180° A B are supplementary M Angles M and N are supplementary. If the measure of is 152°, what is m ? N is 28°

6. Perpendicular Lines Two lines are perpendicular if they intersect at 90° angles n m Are these two lines ? No

7. Parallel Lines • Parallel Lines • Do not intersect • Lie in the same plane k m Are these lines parallel? No; they would intersect if they both continued

8. Transversal A line that “cuts through” two or more other lines (usually the other two are parallel) Which line is the transversal?

9. Corresponding Angles When a transversal cuts through two parallel lines, it creates 4 sets of corresponding angles. Corresponding angles are angles that are in the same position when a transversal cuts two parallel lines. 2 3 4 If I could cut out a whole where this rectangle is, and move it down, each angle would line up with its corresponding angle exactly. 5 6 7 8 Therefore, corresponding angles are congruent.

10. Skew Lines Skew Lines • Lines that do not intersect • Do not lie in the same plane Lines and are skew Lines and are not skew; they are parallel. They lie in the same plane.

11. Apply what you know • Find the measures of the seven missing angles. 125°