Parallel and Perpendicular Lines Objective Learn to recognize parallel and perpendicular lines.

Parallel and Perpendicular Lines… A plane is an infinite, flat surface. Lines in a plane that never meet are called Parallel Lines. Perpendicular Lines: are lines that intersect to form 90 degree angles. For Example:

Lines that intersect 2 or more parallel lines diagonally are called transversal. When a transversal line intersects 2 parallel lines, pairs of congruent angles (angles with the same measures) are formed. Here are some examples… Vertical Angles: <2 and <3; <1 and <4; <6 and <7; <5 and <8. Alternate Interior Angles: < 4 and <5; <3 and <6 Corresponding Angles: < 1 and <5; <3 and <7 <2 and <6; <4 and <8

 Examples: Determine if each pair of lines is parallel, perpendicular, transversal, or neither.  1) 2)  answer: __________ answer:_________  3)  Answer: ___________________

Homework: In 1-8, write the word that best describes the lines. (Parallel or Perpendicular) 1. The strings on a guitar. _______________ 2. Sidewalks on opposite sides of the street. ________________ 3. The lines that make up a plus + sign. ___________________ 4. The hands of the clock at 9pm. _____________________ 5. Two palm trees in Los Angeles. _____________________ 6. The window panes in the classroom. _________________ 7. Ask an adult and name 2 parallel streets. __________________ 8. Ask an adult and name of 2 perpendicular streets. _________________ 9. Look at the picture. Name 2 congruent (same) angles. ________________ 10. Look at the picture and name 2 parallel lines. _____________________