Constant of Proportionality

Direct Variation – constant ratio A direct variation is represented by a ratio or equation : or k ≠ 0 EX1) Determine if the table represents a direct variation. If so, state the constant of proportionality Step 1 Substitute values for variables x 1 2 3 4 y 6 9 12 Step 2 Simplify This is a direct variation because the ratios are constant. The constant of proportionality is 3. K = 3 3 3 3

EX2) Identify the constant of proportionality in the equation y=15x where y = cost of concert tickets and x = number of concert tickets y = 15 x Explain the relationship. Each concert ticket cost $15. y = k x k = constant of proportionality 15 = constant of proportionality 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.

notes

Constant of Proportionality Date ____________ Constant of Proportionality

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

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