The line on a plane can be defined by the slope-intercept equation
Suppose we have two lines with equations and .
For lines to be parallel it is needed that
For lines to be perpendicular it is needed that
This is quite easy for mental calculation, but lines also can be defined by more general form
Then, for lines to be parallel it is needed that
And for lines to be perpendicular is it needed that
So, the calculator below frees you from converting this to slope-intercept form and checks if lines are parallel or perpendicular