Given points C (4,3) and D (2,-5), find the slope of every line parallel to Line CD.
Use the gradient formula.
y2-y1 / x2-x1
3 - (-5) / 4 - 2
8 / 2
Slope = 4
When lines are parallel, they all have the same slope, therefore the slope of every line parallel to CD = 4
Given points R (-2,3) and S (5,1), find the slope of every line perpendicular to Line RS.
Again, gradient formula gives
For any line perpendicular. The gradient changes.
In general, all you do is "flip" the gradient (-2/3) upside down so it becomes (-3/2). Then you multiply the new gradient by -1.
Every line perpendicular to RS will therefore be 3/2
For example if you don't get me.
A line has slope of -1/2.
Perpendicular lines to that line will be 2.