Introduction to Parallel Lines

Identifying Parallel Lines

Parallel lines are lines on a graph that NEVER cross over eachother AND have the SAME EXACT slope.

Multiple Choice

Are any of these lines parallel?

• Yes

• No

If 2 Lines are Parallel, they MUST have the SAME SLOPE!

For example:

y = 2x - 5 and y = 2x + 3

These equations represent parallel lines because they both have a SLOPE (m) of 2.

Multiple Choice

Are these 2 lines parallel? Remember, slope is the number or fraction in front of the x.

• Yes, they are parallel

• No, they are not parallel

Multiple Choice

Are these 2 lines parallel?

• Yes, they are parallel

• No, they are not parallel

Counting Slope:

Rise

------

Run

Multiple Choice

What is the slope of this line? Start at the left point, count the RISE 1st, then count the run.

• 5/2

• 4/1

• -1/4

• 4/3

Multiple Choice

What is the slope of this line? Start at the left point, count DOWN for the rise 1st, then count the run.

• 3/3

• 6

• -3/4

• -4

Slope-Intercept Form

y = mx + b

m is slope

b is y-intercept

Multiple Choice

Which equations represent parallel lines?

Line A: y = 4x + 13

Line B: y = 2x + 13

Line C: y = 4x + 5

• A and B

• A and C

• B and C

Multiple Choice

Which equations represent parallel lines?

Line A: y = 1/2x + 1

Line B: y = 3x - 2

Line C: y = 3x + 4

• A and B

• A and C

• B and C

Multiple Choice

Which lines are parallel to eachother?

• Red and green

• Green and blue

• Red and blue