3.3

Proving Lines are Parallel

Parallel Postulate

Through a point p not on line l there is exactly one line parallel to line l

Converse Thms about Parallel Lines If corresponding angles are congruent … If alternate exterior angles are congruent … If alternate interior angles are congruent … If same-side interior angles are supplementary …

Then, the lines are parallel !!!!

Can you prove any lines are ||?

d

cb

a

112○

110○112○

Ex:If x = 3, are the lines \\?

12y+4

14y4x+12

8x

If y = 11 are the lines \\?

Statement Reason

1. 1.

2. 2.

3. 3.

4. 4.

Given: 1 and 3 are suppProve: m || n

n

m

32

1

Statement Reason

1. 1.

2. 2.

3. 3.

4. 4.

5. 5.

Given : , 1 3

Prove :

c d

a b2

1

3

d

a

c

b

Homework Group Problem Solving Packet

(due end of period)3-2 problem solving #4, 53-3 Problem solving ODDS3-3 Prac B ALL

Book work on syllabus