Finding Slope from a Graph

What is slope? Slope is the steepnes of a line “m” is the symbol used to represent slope

“Slope Poem” I go by several names – pitch, speed, or rate of change Don’t want your brains perplexed so let me explain my steps I’m the change in y divided by the change in x I’m rise over run, the steepness of a line Horizontally zero, vertically undefined

What is the formula for slope?

How to apply the slope formula Example – find the slope of the line that contains points A(0,0) and B(4,3)

Solution to example x₁ = 0, x₂ = 4, y₁ = 0, and y₂ = / 4-0 = ¾ So, the slope of the line containing points A and B is ¾ or 0.75

Notes The steeper the line, the greater the slope A horizontal line has a slope of 0 The slope of a vertical line is undefined Lines that go up and to the right have a positive slope Lines that go down and to the right have a negative slope

For you to try Find the slope of the line containing points A(-6, -5) and B(-3, -7)

Solution x₁ = -6, x₂ = -3, y₁ = -5, y₂ = -7 (-7- -5) / (-3- -6) = -2/3 So, the slope of the line containing points A and B is -2/3 or -0.67

When finding the slope of a line on the coordinate plane… Pick any two points on the line and use their coordinates in the slope formula

Example of finding the slope of a line on the coordinate plane

Solution The two points that the line goes through are (-5,3) and (1,2). So, we can use the slope formula to find the slope of the line. m = (2 – 3) / (1 - -5) m = -1 / 6 or -0.17