#
Section 2-4

#
Slope

Follow the steps below to find the
slope
of any line.

1) Pick any two points on the line. (Pick points with integer coordinates
to make your life easier.)

2) Draw a
vertical line
going down from the higher point.

3) Draw a
horizontal line
from the other point so that it meets the vertical
line.

4) You now have a right triangle, called a slope triangle. Find the lengths
of the vertical and the horizontal legs.

5) Divide the length of the vertical leg (the “rise”) by the
length of the horizontal leg (the “run”). This quotient is the
slope of the line.

So the slope of the line in this example is 1/3.

If the right angle is on the left side of the triangle, the slope is negative.

**
HORIZONTAL AND VERTICAL LINES
**

Horizontal lines have slope zero, since the “rise” is zero.

Vertical lines have undefined slope, since the “run” is zero,
and division by zero is not allowed.