Perpendicular line segments
Rotate the rectangle to turn the line 90 degrees. Notice how the slope of the two lines are related.
Move the red point in each of these diagrams to make the two line segments perpendicular.
Use the triangles to help. You are correct when the angle formed by the line segments is 90 degrees.
Practice #1
Practice #2
Use the practice applet below to refine your technique for making two line segments perpendicular.
When you have a reliable technique, take the quiz.