Question

the slopes of perpendicular lines are?

Answer 1

Negative recipricols of each other
For example
You have a line with a slope of 2/5
The slope of the line perpendicular is -5/2

Another way to look at slopes of perpendicular lines is that their product=-1
In the above example, 2/5(-5/2)=-1

Answer 2

are the negative reciprocals of each other, and a pair of these lines intersects at 90 degrees.