 # Prove Slope of Parallel and Perpendicular Lines

Videos and lessons with examples and solutions to help High School students learn how to prove the slope criteria for parallel and perpendicular lines and use them to solve geometric problems (e.g., find the equation of a line parallel or perpendicular to a given line that passes through a given point).

Common Core: HSG-GPE.B.5

Proof -- slopes of parallel lines are equal & slopes of perpendicular lines are negative reciprocal
1) If two straight lines are parallel, then their slopes are equal.
2) If two straight lines are perpendicular, then the product of their slopes is - 1.

Find the equation of a line parallel or perpendicular to a given line that passes through a given point.

Equations of Parallel and Perpendicular Lines.

Find the Equation of a Line Parallel to a Given Line Passing Through a Given Point.
This video provides an example of how to find the equation of a line that is parallel to a given line in slope-intercept form passing through a given point. This video uses slope-intercept form and point-slope form to find the equation of the line.

Ex 2: Find the Equation of a Line Perpendicular to a Given Line Passing Through a Given Point
This video provides an example of how to find the equation of a line that is perpendicular to a given line in slope-intercept form passing through a given point. This video uses point-slope form to find the equation of the line.

Slope and Equations of Lines through Points
This Demonstration help students practice determining equations of lines given a pair of points, or the line parallel or perpendicular to a given line through a given point. It also gives students a chance to see the relationships between these lines and points.

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