120 likes | 356 Views
Parallel lines and transversals. Corresponding Angles postulate. Two lines cut by a transversal are parallel if and only if the pairs of corresponding angles are congruent. Alternate Interior Angles Theorem.
E N D
Corresponding Angles postulate • Two lines cut by a transversal are parallel if and only if the pairs of corresponding angles are congruent.
Alternate Interior Angles Theorem • Two lines cut by a transversal are parallel if and only if the pairs of alternate interior angles are congruent.
Alternate exterior angles theorem • Two lines but by a transversal are parallel if and only if the pairs of alternate exterior angles are congruent.
Consecutive Interior Angles Theorem • Two lines cut by a transversal are parallel if and only if the pairs of consecutive interior angles are supplementary.
Consecutive exterior angles theorem • Two lines cut by a transversal are parallel if and only if the pairs of consecutive exterior angles are supplementary.
Example • Find each numbered angle.
Example • Find the value of x.
Example • Find the value of x. The picture may not be drawn to scale. (3x + 5)o (7x – 15)o
Transitive property of parallel lines • If two lines are parallel to the same line, then they are parallel to each other.
Assignment • Pg. 157 #4-8 all, 27-35 odds • Pg. 165 #3-8 all