# Parallel and perpendicular lines on a plane

This online calculator checks lines' slopes to see if they are parallel or perpendicular

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

and

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

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