# Slope

## Slope

Rate of variation between two points of a line or a segment in a Cartesian plane.

The term slope of a line is synonymous with the highest degree coefficient of the line. The slope indicates how the line rises when we read it from left to right.

• In a Cartesian plane, the slope m of the line that passes through two given points P(x$$_{1}$$, y$$_{1}$$) and
Q(x$$_{2}$$, y$$_{2}$$) is the ratio of the variation of the y-coordinates to the variation of the x-coordinates.
• When the Cartesian reference point is orthonormal (perpendicular and normed axes), this ratio is called the “slope” and the Cartesian graph is a Cartesian plane. In that case, the slope is the tangent of the angle that the line forms with the x-axis.
• When the Cartesian reference point is not orthonormal, we must use the expression “rate of variation” instead to refer to this ratio.