Perpendicular lines from equation | Mathematics I | High School Math | Khan Academy | Summary and Q&A

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June 12, 2010
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Perpendicular lines from equation | Mathematics I | High School Math | Khan Academy

TL;DR

Two lines are perpendicular if they intersect at right angles and have slopes that are negative inverses of each other.

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Q: What is the definition of perpendicular lines?

Perpendicular lines intersect at right angles and have slopes that are negative inverses of each other.

Q: How can you determine if two lines are perpendicular?

To determine if two lines are perpendicular, you can check if the product of their slopes is equal to -1.

Q: Can two lines with positive slopes be perpendicular?

No, two lines with positive slopes cannot be perpendicular. Perpendicular lines have slopes that are negative inverses of each other.

Q: How can you find the slope of a line in slope-intercept form?

In slope-intercept form (y = mx + b), the coefficient of x represents the slope of the line.

Summary & Key Takeaways

• Perpendicular lines intersect at right angles and have slopes that are negative inverses of each other.

• The product of the slopes of perpendicular lines is always equal to -1.

• Line A and Line B are perpendicular because their slopes, 3 and -1/3, are negative inverses of each other.