When they meet at right angles when plotted on the coordinated grid.
Chat with our AI personalities
If the slope of the equations are the same then they are parallel If the slope of the equations are minus reciprocal then they are perpendicular If the slope of the equations are different then they are neither
Technically, equations are never perpendicular to one another. However, the equations of lines can result in their lines being perpendicular. Using y=mx+b, to have a perpendicular line, you have the negative reciprocal of m.
Depending on the value of the slope or gradient if its the same then they are parallel if its a reciprocal then they are perpendicular.
As far as we know, two lines can be perpendicular, or they can be parallel, but they can't be both.
When the lines intersect at a 90º angle