1. 2.2 Slope and Rate of Change Algebra 2 Mrs. Spitz Fall 2009

2. Objectives Find slopes of lines and classify parallel and perpendicular lines. Use slope to solve problems, such as how to safely adjust a ladder.

3. Assignment pp. 79-80 #4-47 all

4. The slope of a nonvertical line is the ratio of vertical change (the rise) to the horizontal change (the run). The slope of a line is represented by the letter m. Just like any 2 points determine a line, any 2 points are all that are needed to determine the slope. The slope of the line is the same regardless of which 2 points are used

5. The slope of a line The slope of a nonvertical line passing thru the points (x 1,y 1 ) (x 2,y 2 ):

6. Find the slope of a line passing thru (-3,5) & (2,1)

7. Classification of lines by slope A line with positive slope: rises from left to right (m>0) A line with negative slope: falls from left to right (m<0) A line with slope of zero is horizontal (m=0) A line with undefined slope is vertical (m is undefined)

8. W/out graphing, tell whether the line thru the points rises, falls, horizontal, or vertical. 1) (3,-4), (1,-6) 2) (2,-1), (2,5) Undefined: The line is vertical m>0, the line rises

9. Not only does slope tell you whether the line rises, falls, is horizontal, or is vertical; it also tells you the steepness of the line For two lines, the line slope of greater absolute value is steeper.

10. Tell which line is steeper Line 1 thru (2,3) & (4,7) or Line 2 thru (-1,2) & (4,5) Since the lines have positive slope & m 1 >m 2 line 1 is steeper