The slope of a line perpendicular to a line with slope x is -[tex] \frac{1}{x} [/tex]. it is the opposite reciprocal. The slope of this line is 4/5. The first step in finding the slope of a line perpendicular to this line is to take the reciprocal of it, which gives us 5/4. The final step is to multiply it by negative 1. This gives us our answer of -5/4.
