Perpendicular Lines in the Coordinate Plane: Quick Exploration

What does it mean for lines to be perpendicular (by definition)?

Reposition line f below so that its slope becomes 4/3. Then slowly slide the slider you see all the way to the right.

If the [b][color=#bf9000]slope of line [i]f[/i][/color][/b] [i]= [math]\frac{4}{3}[/math][/i] and line [i][b]g[/b][/i] is perpendicular to line [i]f[/i], [b]what is the slope of line [i]g[/i][/b]? [br]If you forget how to find the slope of a line by inspection, click here for a quick reminder.

[math]\frac{3}{4}[/math] [math]-\frac{3}{4}[/math] [math]-\frac{4}{3}[/math] [math]\frac{4}{3}[/math]

Reposition line f below so that its slope becomes -2/5. Then slowly slide the slider you see all the way to the right.

If the [b][color=#ff00ff]slope of line [i]f[/i] [/color][/b]= [math]-\frac{2}{5}[/math] and line [i][b]g[/b][/i] is perpendicular to line [i]f[/i], [b]what is the slope of line [i]g[/i][/b]? [br]If you forget how to find the slope of a line by inspection, click here for a quick reminder.

[math]-\frac{5}{2}[/math] [math]\frac{5}{2}[/math] [math]-\frac{2}{5}[/math] [math]\frac{2}{5}[/math]

Notice anything interesting between slopes of perpendicular lines drawn in the coordinate plane? If so, please describe.

Information: Perpendicular Lines in the Coordinate Plane: Quick Exploration