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Slope of a Line

The slope m of a line passing through 2 points ( 10 1 , y 1 ) and ( x two , y 2 ) is:

m = y 2 y 1 ten 2 x i

If the graph of a line rises from left to right, the slope is positive.  If the graph of the line falls from left to correct the slope is negative.

Case:

Find the gradient of the line passing through the points ( 3 , 17 ) and ( 4 , 3 ) .

Substituting x 1 = 3 , y 1 = 17 , x two = 4 , and y 2 = 3 , nosotros go:

g = 3 17 4 ( 3 ) = 14 seven = 2

So the gradient is 2 .

Yous can follow the steps below to find the slope of any line.

1 ) Pick any two points on the line. (Pick points with integer coordinates to make your life easier.)

ii ) Draw a vertical line going down from the higher point.

iii ) Draw a horizontal line from the other point so that it meets the vertical line.

4 ) You lot at present have a right triangle, called a slope triangle. Discover the lengths of the vertical and the horizontal legs.

5 ) Dissever the length of the vertical leg (the "rise") by the length of the horizontal leg (the "run"). This caliber is the gradient of the line.

rise run = ii 6 = i 3

So the slope of the line in this example is 1 3 .

If the correct bending is on the left side of the triangle, the slope is negative.

Horizontal and Vertical Lines

Horizontal lines have gradient zero, since the "rise" is zero.

Vertical lines have undefined slope, since the "run" is goose egg, and partitioning by nil is not allowed.