Post on 05-Jan-2016
description
Chapter 3Section 3-1: Properties of
Parallel Lines
Goal 2.02: Apply properties, definitions, and theorems of angles
and lines to solve problems and write problems and write proofs.
Turn in Cumulative Review
Check Skills: p 115 (1-6)
Essential Questions
1. How are angles formed by 2 lines and a transversal identified?
2. How are the properties of parallel lines used to determine angle measure?
Transversal
a line that intersects two or more coplanar lines in different points
Alternate Interior Angles
(alt. int. ‘s) two nonadjacent interior angles on opposite side of the transversal
Same-Side Interior Angles
Also called consecutive angles
(s-s int. ‘s) two interior angles on the same side of the transversal
Corresponding Angles
(corres. ‘s) two angles in corresponding positions relative to the two lines
Examples, p 118
5)
7)
Together: p 118-119 (6,8)
Examples
1) 2 and 3
3) SPQ and PSR
Together: 2, 4
Theorem about Parallel Planes
If two parallel planes are cut by a third plane, then the lines of intersection are parallel.
Example
Use # 9 for 4th property of: if 2 parallel lines are cut by a transversal then ….
P. 119 11.13.15.
P 120Two lines and a transversal form how many pairs
of the following? 19 Alternate interior angles 20 corresponding angles 21 same-side interior angles 22 vertical angles
Postulate and Theorems about angles formed by 2 Parallel lines and a transversal
If two parallel lines are cut by a transversal, then the corresponding angles are congruent. (post)
If two parallel lines are cut by a transversal, then alternate interior angles are congruent.
If two parallel lines are cut by a transversal, then same-side interior angles are supplementary.
If a transversal is perpendicular to one of two parallel lines, then it is perpendicular to the other also.
Practice
• With a partner: p 119 (12- 16 even) p 120 (23-25 all)Go over.
Individually: Practice 3-1 Worksheet
Summarize
List the 4 things you know if 2 parallel lines are cut by a transversal.
1.2.3.4.
Standardized Test Prep: p. 121 (37-41 all)
Homework
• Mixed Review: p 121 (42- 50 all)• Worksheet: Definitions worksheet Review