Find a Perpendicular Line Through a Point - Calculator

A calculator to find the equation of a line that is perpendicular to a given line and passing through a point.

Equation of a Line Perpendicular to Another Line and Through a point P

The slope \( m \) of line L given by the equation \( A x + B y = C \) is given by \[ m = - \dfrac{A}{B} \] If two lines are perpendicular, the product of their slopes is equal to \(-1\) \[ m \cdot m' = - 1 \] Hence the slope of the line perpendicular to line L is given by \[ m' = \dfrac{-1}{- \dfrac{A}{B}} = \dfrac{B}{A} \] The equation, in point slope form, of a line parallel to line L and through point P (a,b) is given by \[ y - b = \dfrac{B}{A} (x - a) \]

How to use the calculator

1 - Enter the coordinates of the point through which the line passes.
2 - Enter A, B and C the coefficients of the the given line defined as follows. \[ A x + B y = C \] 3 - press "enter". The answer is an equation, in slope intercept form, of the line perpendicular to the line entered and passing through the point entered .
The coordinates and coefficients may be entered as fractions, integers or decimals.(see examples below).

Point: ( , )
Line: x + y =


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