Warm Up Using the graphic organizer on page 23 fill in the angles pairs. (we will complete the sentences together in a few minutes).

HW Check – pg 24 Corresponding alt interior 3) Same side interior 4) alt interior 5) Same side interior 6) corresponding 7) 1 & 5 , 4 & 7, 2 & 6, 3 & 8 8) 4 & 6, 3 & 5 9) 4 & 5, 3 & 6

From Monday’s notes… Complementary – Two angles whose measures have a sum of 90º Supplementary – Two angles whose measures have a sum of 180º

Practice with Supplemental Angles Find the missing Angle: Find x:

Let’s look at a pair of parallel lines cut by a transversal. What kind of angles are 1 and 2? Corresponding If we TRANSLATE the bottom line upward, what do we notice? 1 Ask what translate means! It’s the same angles 2

Properties of Parallel Lines

Let’s look further… Suppose mb = 60 Use what you know about vertical, supplementary, and corresponding angles to find the measures of all the other angles Can we make any conclusions?

More Postulates When a transversal intersects two parallel lines, we have two other interesting angle properties

II. This is easy to remember because we know about vertical angles and corresponding angles!

III. This is easy because we know supp (linear pair) and corr

Two options for angles with parallel lines and transversals Either the two angles are congruent (Vertical angles, Alternate, Corresponding) or they add to 180 (same side interior, same side exterior, create straight line)

Find x

Create and equations and solve

Class Work Pgs 25 – 26 Evens Homework Pgs 25 – 26 Odds

More Definitions Bisect – to divide a line/angle/shape into two equal parts Perpendicular Bisector - A line which cuts a line segment into two equal parts at a right angle (90°).

Set up equations using the properties of parallel lines cut by a transversal to solve.