1. At the end of this lesson you will be able to: Determine the names of angles based on their degree of measurement. Determine the names and properties of different kinds of lines. Associate the information on angles and lines to objects in their environment. Determine the degree of precision needed for each situation L 18: Lines and Angles

2. Types of Lines Parallel: two lines equidistant that never touch_____________ _____________ Perpendicular: meeting at right angles ______________

3. Types of Angles As we deal with angles we are going to learn some new vocabulary that goes with angles. Some of these vocabulary terms will seem familiar because we have used them in connection with triangles.

4. Acute Angle Acute Angle – An angle that is less than 90 0

5. Obtuse Angle Obtuse Angle – An angle that is greater than 90 0 and less than 180 0

6. Right Angle Right Angle – An angle that measures 90 0

7. Straight Angle Straight Angle – An angle that measures 180 0 (a straight line)

8. Complimentary Angles Complimentary Angles – Two angles whose sum equals 90 0

9. Supplementary Angles Supplementary Angles – Two angles whose sum equals 180 0

10. Vertical Angles Vertical angles are opposite each other when 2 lines cross. They are always equal. If angle a is 40 degrees, what is angle b?

11. Other kinds of matching angles This is an important shape to watch out for! Two parallel lines cut by a transversal (a line crossing them like an intersection). They are like two matching vertical angles! Matching angles are all equal.