## Presentation on theme: "Homework Answers."— Presentation transcript:

Parallel and Perpendicular lines

Select two parallel lines that are at least six spaces from each other and in the center of your paper. Retrace them in pen to make them darker.

Draw another line (not perpendicular) that goes through both of your parallel lines.
This line is called a transversal.

Number the angles as shown
1 2 3 4 5 6 7 8

Use your protractor to measure the angles formed by the transversal and the parallel lines. Color congruent angles the same color.

Fill in the blanks. What do you notice?
1 ______ 4 ______ 5 ______ 8 ______ 2 ______ 3 ______ 6 ______ 7 ______ What do you notice? 1 4 5 8 2 3 6 7

Properties of Transversals to Parallel Lines
If two parallel lines are intersected by a transversal The acute angles that are formed are all congruent The obtuse angles are all congruent Any acute angle is supplementary to any obtuse angle

If the transversal is perpendicular to the parallel lines, all angles formed are congruent to 90o.

Relationships Alternate interior angles

Relationships Alternate exterior angles

Relationships Corresponding angles

Open your books to page 230.