Slope Formula (rise/run)?

Question

Hi,

I have learned from previous math classes that for the slope formula, you can rise either up or down; but when you run, it is always to the right. ALWAYS.

But for my current math class, my teacher gives me the following notes:

"Use the slope to rise and run to the next point. Remember you always rise; but when you run, you can run in either direction. If the slope is negative, then run is the negative X direction. Oppositely, if the slope is positive, then the run is in the positive X direction."

Am I mistakening her meaning behind that brief summary? I'm confused, since I was taught in previous classes that I must always run right. But now, I'm being told otherwise.

Can someone help clarify me on the actual rules for the slope?

TQA. And have a happy 2007.

Answer 1

Favorite Answer

Now you're probably REALLY confused. :P The fact is, both teachers were correct, because (believe it or not) they were both saying exactly the same thing. The way to combine what they both said into a single rule is as follows:

Choose which measurement (rise or run) to always measure in the same direction (up or right). Then the other measurement can be in either direction.

I actually don't follow the above rule. I just measure the rise and run without worrying about their individual directions. Then I inspect the line itself to see which way it's rotated relative to the y-axis. If clockwise (up to 90 degrees), it's a positive slope. If counterclockwise (up to 90 degrees), it's a negative slope.

Answer 2

The current maths class teacher is correct. Previous math class was only considering the positive slope, which is only half the story

Answer 3

slope formula:

y1-y2/x1-x2