LINES AND ANGLES
The slope is
75 . Using an Equation to Find an Intercept
To find the y-intercept, you can either put the equation into y = mx + b
(slope-intercept) form—in which case b is the y-intercept—or you can just
plug x = 0 into the equation and solve for y. To find the x-intercept, plug y =
0 into the equation and solve for x.
76 . Finding the Midpoint
The midpoint of two points on a line segment is the average of the x-
coordinates of the endpoints and the average of the y-coordinates of the
endpoints. If the endpoints are (x 1 ,y 1 ) and (x 2 ,y 2 ), the midpoint is
The midpoint of (3,5) and (9,1) is or (6, 3).
77 . Intersecting Lines
When two lines intersect, adjacent angles are supplementary, and
vertical angles are equal.
