What is the relationship between the slopes of perpendicular lines?

The slopes are negative reciprocals of each other.

Equations Of Parallel And Perpendicular Lines Lesson Plan for Grade 9th Grade

Name: Equations of Parallel and Perpendicular Lines
Author: Insta~Lesson

I can write an equation for a parallel or perpendicular line given another line and a point

1
Parallel lines have the same slope, while perpendicular lines have opposite reciprocal slopes.
2
The point-slope equation, which is y - y₁ = m(x - x₁), can be used to find the equation of a line if you know the slope and a point on the line.
3
To find the equation of a parallel or perpendicular line, first identify the slope of the given line, then determine the slope of YOUR line. (Remember: you will need the SAME slope for parallel lines and the opposite reciprocal slope for perpendicular lines). Finally, use the point-slope equation to find the new equation.