4.4 Slope Formula

Slope can be expressed different ways: UP or DOWN RIGHT A line has a positive slope if it is going uphill from left to right. A line has a negative slope if it is going downhill from left to right.

Rise Run 4 THE SLOPE IS 3 4 3 Discuss vertical change

Find the slope of the following line. The slope is… 1 2

Find the slope of the line. The slope is…. -3

1) Determine the slope of the line. When given the graph, it is easier to apply “rise over run”.

Determine the slope of the line shown.

What is the slope of a horizontal line? The line doesn’t rise! All horizontal lines have a slope of 0.

What is the slope of a vertical line? The line doesn’t run! All vertical lines have an undefined slope.

REMEMBER THE SLOPE FORMULA???!!!!! Let’s find the slope of a line with two points, WITHOUT LOOKING AT A GRAPH. REMEMBER THE SLOPE FORMULA???!!!!!

2) Find the slope of the line that passes through the points (-2, -2) and (4, 1). When given points, it is easier to use the formula! y2 is the y coordinate of the 2nd ordered pair (y2 = 1) y1 is the y coordinate of the 1st ordered pair (y1 = -2)

3) Find the slope of the line that goes through the points (-5, 3) and (2, 1). x1 y1 x2 y2

Sample Problems: Find the slope of the line thru the points given: (-3,-1) and (-2,4) (-3,4) and (2,-2) x1 y1 x2 y2 x1 y1 x2 y2

Independent Practice: Calculate the slope for each pair of points Independent Practice: Calculate the slope for each pair of points. Classify each slope as positive, negative, zero, or undefined. 1. (2, 2) and (3, 5) 2. (0, 0) and (3, 0) Slope: 3 Classification: Positive Slope: 0 Classification: Horizontal 3. (-2, -1) and (-1, -4) 4. (2, 3) and (2, 7) Slope: -3 Classification: Negative Slope: Undefined Classification: Vertical 5. (-1, -1) and (5, 5) 6. (8, 4) and (6, 4) Slope: 1 Classification: Positive Slope: 0 Classification: Zero