Perpendicular lines have _________ slopes?
"Flip the fraction and change the sign"
One word might be "opposite" slopes.
They run in opposite directions, and as steep as one is, as gentle is the other.
The opposite of "steep to the left" is "gentle to the right"
The opposite of "x's to the right " is 'lots of y's to the left"
ONe slope is the negative reciprocal of the other.
IN easy parlance...."Flip the fraction and change the sign"