The steepness of a hill is called a slope. The same goes for the
steepness of a line. The slope is defined a s the ratio of the
vertical change between two points, the rise, to the horizontal
change between the same two points, the run.
The slope of a line is usually represented by the letter m.
(x1, y1) represents the first point whereas
(x2, y2) represents the second point.
It is important to keep the x-and y-coordinates in the same
order in both the numerator and the denominator otherwise you will
get the wrong slope.
Find the slope of the line
(x1, y1) = (-3, -2) and (x2,
y2) = (2, 2)
A line with a positive slope (m > 0), as the line above,
rises from left to right whereas a line with a negative slope (m
< 0) falls from left to right.
A line with the slope zero (m = 0) is horizontal whereas a line
with an undefined slope is vertical.
In earlier chapters we have looked at how fast a car drives and
talked about speed in miles per hour. This is an example of the
rate of change. The rate of change compares a change in one
quantity to a change in another quantity like at what speed does a
car travel if it travels 120 miles in 2 hours?
You can interpret a slope of a line as the rate of change.
Videolesson: Find the slope of the line