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Khan Academy

Khan Academy: Parallel & Perpendicular Lines From Equation

For Students 9th - 10th Standards
Use your knowledge about the slopes of parallel and perpendicular lines to solve some problems. For example, what's the equation of the lineperpendicular to y=3x-3 and passes through the point (-8, -2).
Unknown Type
Khan Academy

Khan Academy: Parallel & Perpendicular Lines From Graph

For Students 9th - 10th Standards
Given points that two lines go through or the graph of each line, classify the lines as parallel, perpendicular, or neither.
Lesson Plan
PBS

Pbs Learning Media: Math + Arts: Perspective Drawing

For Teachers 3rd - 5th
In this lesson, students use line segments, angles, and parallel and perpendicular lines in order to create a one point perspective drawing.