Writing Equations of Parallel Lines

Writing Equations of Parallel Lines

How can we determine if lines are parallel?

Parallel and Slopes

• Two lines in the same plane that never intersect.

• Two lines are parallel if and only if they have the same slope.

Identifying parallel lines

• Find the slope of each line

• When a graph is present we can use rise/run

• Use ll symbol to write which lines are parallel

Multiple Choice

Determine which lines are parallel

• a ll b

• b ll c

• c ll a

Identifying Parallel Lines

When there is no graph present, use the slope formula y2-y1/ x2-x1.

Then compare slopes

Multiple Choice

Determine which lines are parallel.

• a ll b

• b ll c

• a ll c

Multiple Choice

Determine which lines are parallel.

• a ll b

• b ll c

• a ll c

• None

Poll

Should we have homework tonight?

• Yes

• No