Lesson: Parallel and Perpendicular Lines

Multiple Choice

Do you have your phone away, notebook out, and ready to take notes? ​

(you will need to take a picture and upload it at the end)

• YES I have my notebook out

• No, I know it means a bad grade

Parallel and Perpendicular Lines

Objective: Identify parallel and perpendicular line given the equations.

Multiple Choice

REVIEW: What is the slope of the line:  $$y=\frac{2}{3}x+4$$  

• $$\frac{2}{3}$$  

• $$-\frac{2}{3}$$  

• $$\frac{3}{2}$$  

• $$4$$  

• $$-4$$  

Parallel Lines

Lines side by side and having the same distance continuously between them

SLOPE of Parallel Lines

In the coordinate plane,

Parallel Lines have the SAME SLOPE

Multiple Select

Which two lines are parallel?

• $$y=\frac{3}{7}x-25$$

• $$y=\frac{3}{7}x+2$$

• $$y=\frac{7}{3}x-25$$

• $$y=3x+13$$

• $$y=7x+9$$

What about equations in different forms?

​Are y = 2x + 4 and y - 19 = 2(x + 21) parallel?

But...

What about equations in different forms?

​Are y = 2x + 4 and 2x + 5y = 10 parallel?

Multiple Choice

Which line is parallel to the line:  $$5x+6y=12$$  

• $$y=-\frac{5}{6}x-2$$  

• $$y=\frac{5}{6}x+13$$  

• $$y=5x+11$$  

• $$y=-5x-100$$  

Perpendicular Lines

Lines that intersect at a right (90 degree) angle

RECIPROCAL

​Simple definition is a fraction flipped.

​EXAMPLE

SLOPES of Perpendicular Lines

In the coordinate plane, Perpendicular Lines

have slopes that are OPPOSITE RECIPROCALS

Multiple Select

Which two lines are perpendicular?

• $$y=\frac{3}{7}x-25$$

• $$y=-\frac{3}{7}x+2$$

• $$y=-\frac{7}{3}x-25$$

• $$y=3x+13$$

• $$y=7x+9$$

What about equations in different forms?

Multiple Choice

Which line is perpendicular to the line:  $$5x+6y=12$$  

• $$y=-\frac{5}{6}x-2$$  

• $$y=\frac{5}{6}x+13$$  

• $$y=\frac{6}{5}x+11$$  

• $$y=-\frac{6}{5}x-100$$