Perpendicular Lines Investigation Group C
Two lines are perpendicular to each other if they intersect each other at 90 degrees. Is[br]there any relationship between the gradients of perpendicular lines?
1
The diagram above show two lines which are perpendicular to each other. The lines are [i]y[/i] = [i]x[/i] +2 and[br][i] y[/i] = -[i]x[/i] + 2. What is the gradient of Line 1? What is the gradient of Line 2?
2
The Geogebra Applet shows two perpendicular lines and the gradients (slopes) of these lines. Drag the blue point to get different sets of perpendicular lines. Jot down the gradients of 4 sets you try.[br]Eg. Set 1 : m[sub]1[/sub]=?, m[sub]2[/sub]=?[br] Set 2 : m[sub]1[/sub]=?, m[sub]2[/sub]=?[br]
Conclusion : The lines [i]y[/i] = m[sub]1[/sub][i]x[/i] + c[sub]1[/sub] and [i]y[/i] = m[sub]2[/sub][i]x[/i] + c[sub]2 [/sub]are perpendicular if[br]and only if ______________________________.