Objective The student will be able to: find the slope of a line given 2 points and a graph. \

What is the meaning of this sign? Icy Road Ahead Steep Road Ahead Curvy Road Ahead Trucks Entering Highway Ahead

Slope is the steepness of a line. What does the 7% mean? 7% 7% is the slope of the road. It means the road drops 7 feet vertically for every 100 feet horizontally. 7 feet 100 feet So, what is slope??? Slope is the steepness of a line.

Slope can be expressed different ways: 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.

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

Notice the slope is positive AND the line increases! Answer: Start with the lower point and count how much you rise and run to get to the other point! rise 3 = = run 6 6 3 Notice the slope is positive AND the line increases!

2) Find the slope of the line that passes through the points (-2, -2) and (4, 1). USE THE FORMULA!!

Answer: 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)

You can do the problems either way! Which one do you think is easiest? Did you notice that Example #1 and Example #2 were the same problem written differently? 6 3 (-2, -2) and (4, 1) You can do the problems either way! Which one do you think is easiest?

3. Find the slope of the line that passes through (3, 5) and (-1, 4). -4 ¼ - ¼

4). Find the slope of the line that goes through the points (-5, 3) and (2, 1).

ANSWER:

5. Determine the slope of the line shown. -2 -½ ½ 2

The line is decreasing (slope is negative). ANSWER -1 Find points on the graph. Use two of them and apply rise over run. 2 The line is decreasing (slope is negative).

6. What is the slope of a horizontal line?

Answer: The line doesn’t rise! All horizontal lines have a slope of 0.

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

Remember the word “VUXHOY” Vertical lines Undefined slope X = number; This is the equation of the line. Horizontal lines O - zero is the slope Y = number; This is the equation of the line.

7. ZIPLINE! An engineer needs to determine the slope between two points on a zipline cable in order to evaluate the breaking power required for passengers to stop safely. A coordinate grid has been placed over a diagram between the two points, as shown below. For estimation purposes, a straight line between the two points can be used to find the slope. Assuming the cable runs in a straight line, what is the slope of the line between the two points shown? Please use the SLOPE FORMULA to show your work. Explain what the slope ‘means’ in terms of the problem (how is this will the engineer use the information)Write your answer in complete sentences.

PRACTICE 8. What value represents the slope in the equation: y=3x +4 9. What is the slope given the table: 10. What is the slope between the 2 points (3,5) and (8,4) ? X Y 5 2 3 4

Additional Resources Video http://www.virtualnerd.com/tutorials/?id=Alg1_10_1_2 (watch the video to review how to find the slope between 2 points) http://www.mathplayground.com/SaveTheZogs/SaveTheZogs.html http://hotmath.com/hotmath_help/games/kp/kp_hotmath_sound.swf

Additional http://hotmath.com/hotmath_help/games/kp/kp_hotmath_sound.swf http://www.ixl.com/math/grade-8/find-the-slope-of-a-graph