1. Constant of Proportionality

2. A direct variation is represented by a ratio or equation : or k ≠ 0 Direct Variation – constant ratio EX1) Determine if the table represents a direct variation. If so, state the constant of proportionality Step 1Substitute values for variables K =33 33 Step 2Simplify This is a direct variation because the ratios are constant. The constant of proportionality is 3.

3. EX2)Identify the constant of proportionality in the equation y=15x where y = 15 x k = constant of proportionality y = k x 15 = constant of proportionality Explain the relationship. y = cost of concert tickets andx = number of concert tickets Each concert ticket cost $15. EX3) Refer to the graph. Is there a direct variation? Explain There is not a direct variation. The line does not go through the origin.

4. EX4) Refer to the graph. Is there a direct variation? Explain There is a direct variation. The line goes through the origin. 3 12 $ 21 Month 36 What is the constant of proportionality? Explain $3 per month. Constant of proportionality is Y/X when X is 1.

5. Essential Question How can you determine if a relationship is a direct variation from an equation? A table? A gragh?

6. Constant of Proportionality Date ____________

7. A direct variation is represented by a ratio or equation : Direct Variation – EX1) x y Determine if the table represents a direct variation. Step 1 Step 2

8. EX2)Identify the constant of proportionality. y = 15 x k = Explain the relationship. y = x = EX3) Refer to the graph. Is there a direct variation? Explain

9. EX4) Refer to the graph. Is there a direct variation? Explain 3 12 $ 21 Month 36 What is the constant of proportionality? Explain

10. Essential Question How can you determine if a relationship is a direct variation from an equation? A table? A gragh?