Direct Variation Equation

What is the constant rate of proportionality?

What is the constant of proportionality? 

 What is the direct variation equation? 

Do the following ordered pairs represent a proportional relationship:  (2, 3), (4, 6), (6, 9), (8, 12)

 Explain why or why not.  If yes, what is the constant of proportionality/constant of variation?

Does the following equation represent a direct variation:  y = 5 + x    Explain why or why not.

A square with side length n is shown below.  Which equation represents the proportional relationship between perimeter and side length?

• n = 4P

• P = 4 + n

• P = 4n

Assume y varies directly with x, write an equation for the direct variation. Then find the value of the variable asked for.

If y = -4 when x = 10, find y when x = 5.

Assume y varies directly with x, write an equation for the direct variation. Then find the value of the variable asked for.

If y = 12 when x = -15, find y when x = 2.

Assume y varies directly with x, write an equation for the direct variation. Then find the value of the variable asked for. Find x when y = 18, if y = 9 when x = 8.

What ordered pair represents the unit rate?