4.1 Rate of Change and Slope Take a look at Example #1 on page 187 What is the rate of change and what does it mean? This means that it costs $39 per game.

Now try Check Your Progress 1A & 1B on page 188 Answers: 1A: 16/1 1B: 16 square inches of surface is tiled for each floor tile that is used.

Slope Begin 29:27 or -13:13 End 35:03 or -7:37

Slope Given the two points: (3, -5) & (-2, 7) find the slope of the line. Negative slope means the line “Falls” or goes “Down the Mountain” Positive slope means the line “Rises” or goes “Up the Mountain”

1) Locate two points on the given line. Determine how many units it takes to “rise” (positive) or “fall” (negative) to get to the level of the next point. Determine how many units it takes to “run” (right = positive, left = negative) to reach the point. 2 1

Slope Horizontal line has a slope of 0 (zero). Because zero divided by any number is still zero. Vertical line has a slope of undefined. Because you can never divide by zero.

Find the coordinates given the slope Find the value of r so that the line through (6, 3) and (r, 2) has a slope of ½. cross multiply Set the slope equal to the formula with the given points plugged in. solve for r

Homework #26 Worksheet – Ducks p. 193 32-35, 44-47