Bell Work
Write the equation in
1) point-slope form
2) slope-intercept form
3) standard form
for a line through (-2,8) with slope
8
5
4.4 Parallel and Perpendicular Lines
Parallel Lines: Lines in the same plane that do not intersect.
 All vertical lines are parallel.
 Nonvertical parallel lines have the same slope.
Perpendicular Lines: Lines that intersect at right angles.
 Vertical lines and horizontal lines are perpendicular.
 The slopes of nonvertical perpendicular lines are
opposite reciprocals – they multiply to be -1.
Example #1
Write an equation in slope-intercept form for the line that passes through (-3,5) and is
parallel to the graph of y = 2x – 4.
Example #2
Write an equation in slope-intercept form for the line that passes through (-4,6) and is
perpendicular to the graph of 2x + 3y = 12.
Example #3
Determine whether the graphs of
6x – 2y = -2 and y = 3x – 4 and y = 4 are parallel or perpendicular.
Example #4
Given the graph find all parallel lines and perpendicular lines.
Homework:
4.4(pg.243-244) #12,17,18,22,24,30,34-36,44