Perpendicular Line Calculator

Find the equation of the line perpendicular to y = mx + b that passes through a given point (x, y). The new slope is the negative reciprocal of m.

Frequently Asked Questions

How do you find the slope of a perpendicular line?

Take the negative reciprocal. If the reference slope is m and is not zero, the perpendicular slope is minus one divided by m. For zero slope, the perpendicular is vertical.

Why is the slope product minus one?

For two non-vertical lines to meet at a right angle, their slopes m and m prime satisfy m times m prime equals minus one - a consequence of the dot product of their direction vectors equaling zero.

What if the original line is vertical?

A vertical line has the form x equals constant. Any horizontal line y equals constant is perpendicular to it.

Important Disclaimer: Estimates for informational purposes only.

This calculator provides estimates for informational purposes only. Results are based on assumptions and may not reflect actual outcomes. Consult qualified professionals in relevant fields before making important decisions based on these results.