1.  Do Now: 1. Take out HW. 2. Copy down HW. 3. What are all the theorems we use to prove 2 lines are parallel?

2. 5 cards

3.  Fold one piece of patty paper in quarters What do we know about the 4 angles created?

4.  Theorem 3.9 If two lines are perpendicular, then they intersect to form 4 right angles.

5.  Theorem 3.8 If two lines intersect to form a linear pair of congruent angles, then the lines are perpendicular.

6.  Patty Paper Fold the paper in quarters, then fold one of the quarters in half.

7.  Theorem 3.10 If two sides of two adjacent acute angles are perpendicular, then the angles are complementary.

8.  Patty Paper Fold two parallel lines, then fold a third line that is perpendicular to one of the first lines.

9.  Theorem 3.11: Perpendicular Transversal Theorem If a transversal is perpendicular to one of two parallel lines then it is perpendicular to the other.

10.  Theorem 3.12: Lines Perpendicular to a Transversal Theorem If two lines are perpendicular to the same line, then they are parallel to each other.

11.  Example 1: Which Theorem Justifies the Statement? 1 2

12.  Example 2: Explain how you would show that the lines are parallel. 1 2

13.  Example 3: Find the value of x 8x-2 22◦

14.  Exit Slip: Draw the diagram. Which lines are parallel?