Parallel & Perpendicular Line Calculator
How It Works
This parallel & perpendicular line calculator uses established formulas to provide accurate results.
The basic rule:
- Parallel lines: m₂ = m₁
- Perpendicular lines: m₂ = -1/m₁
- y - y₁ = m₂(x - x₁)
Results are estimates. Consult a professional for critical decisions.
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Explore Allday Everyday Math →Frequently Asked Questions
What makes lines parallel?
Parallel lines have the same slope but different y-intercepts. They never intersect. If one line has slope 3, any parallel line also has slope 3.
What makes lines perpendicular?
Perpendicular lines intersect at a 90° angle. Their slopes are negative reciprocals of each other. If one slope is 2, the perpendicular slope is -1/2.
What is a negative reciprocal?
To find the negative reciprocal, flip the fraction and change the sign. For example: 3 becomes -1/3, -2/5 becomes 5/2, and 1 becomes -1.