3-6+&+3-7+Lines+in+the+Coordinate+Plane

In these two sections, you will learn how to figure out if two lines on a coordinate plane are parallel or perpendicular. Also, what the slopes of the lines have to be to know if they are perpendicular or parallel.
 * 3-6 & 3-7 Parallel and Perpendicula****r Lines in the Coordinate Plane**
 * Slope:**
 * (**x1, y1) and (x2, y2)

y= mx+b
 * Slope-Intercept Form:**
 * Slope****=** m
 * y****-intercept**= (0,b)

y-y1= m(x-x1)
 * Point-Slope Form**

In a coordinate plane, two non vertical lines are parallel if and only if they have the __same slope__. Any two vertical lines are parallel.

In a coordinate plane, two non vertical lines are perpendicular if the product of their slops is __-1__. Vertical and horizontal lines are perpendicular. Slopes are opposite reciprocals.


 * Examples from the textbook pages: 165-166**



1) Write an Equation of a line that passes through point B and is parallel to the line of the given equation. L(6,1), undefined slope
 * Examples:**

2) Write an equation of the line that has a y-intercept of 3 and is parallel to the line of the given equation. y= -6x + 2

1) x=6 2) y= -6x + 3
 * Answers:**

Decide whether the lines are perpendicular. 1) line L: y= 3x line S: y= -1/3x - 2
 * Examples from the textbook: Pages 172-17**
 * Examples:**

2) Decide whether the lines are perpendicular, parallel, or neither y= -2x - 1 y= -2x - 3

1) yes, they are perpendicular 2) Parallel
 * Answers:**

http://www.mathopenref.com/coordparallel.html http://www.mathopenref.com/coordperpendicular.html
 * Links:**