how do you find the slope of a line sagment?
you are given two points which define a line segment.
Find the slope of the line sagment, and then use this
slope to write the equation of a parallel line [and a]
perpendicular line which pass through the new y-intercept
1. line segment (1,8) and (7,-4) y-intercept of new lines: (0,-7)
The slope is (y2 - y1) / (x2 - x1)
m = (-4 - 8) / (7 - 1) = -12/6 = -2
This line segment is y = -2x + b. We don't know the y-intercept,
but we are not concerned with that. A parallel line has the same
slope but a different y-intercept. We are given the y-intercept,
so the equation is y = -2x - 7.
A line perpendicular to the given line segment has a slope that
is the negative reciprocal: 1/2. The equation of that line is
y = (1/2)x - 7.