because it is
The slope of a graph is a measure of the rate at which it rises. It is measured as the "rise"/"run" which is the ratio of the increase in height for each unit move in the horizontal direction. The slope of a line going from bottom left to top right is positive. "M" stood for the Modulus of slope.
The steepness of a line can be measured as the slope of a line. The letter 'm' is used to denote the slope and it can be expressed as m= (y coordinate of A- y coordinate of B)/ (x coordinate of A- x coordinate of B). A and B are two points on the line.
M refers to the modulus of the slope.
The slope of a line perpendicular to one with a slope of m is -1/m.
If the slope of a line is m then the slope of an altitude to that line is -1/m.
m = slope
Slope of a line = m slope of perpendicular line = -1/m
If we call the slope m we can say that the slope of the perpendicular line is -1/m In this case as the slope, m, is 13 the slope of the perpendicular is -1/13 or -0.07692307692
slope = m = (∆y) / (∆x) = rise / run
It is the slope.
The derived unit used to measure the slope of a line in a graph is meters per second (m/s) for velocity or meters (m) per second squared (m/s^2) for acceleration. This represents how the value of the y-coordinate changes per unit change in the x-coordinate.
It is not documented why the letter m was chosen for slope. However, mathematician John Conway suggested that m could mean 'modulus of slope'.