Perpendicular & Parallel Slope Calculator

Find the perpendicular slope (negative reciprocal) and parallel slope for any line. Two input modes: enter a slope directly as a number or fraction like 3/4, or enter two points (x₁, y₁) and (x₂, y₂) and the calculator computes the slope for you. Perpendicular lines have slopes whose product is −1, and the step-by-step work verifies this relationship. The calculator handles special cases — vertical and horizontal lines — and displays all results as simplified fractions.