#### Understanding

Ordered pairs that satisfy equations of the form y = ax + b with b ≠ 0 will not lie on a line through the origin and so will not belong to a collection of equivalent ratios.

### What to look for

To find a line representing a particular proportional relationship, students might first identify two points in the associated ratio and move the points on the screen to these points using the horizontal and vertical arrows.### Sample Assessment

Cost in dollars, c, and amount of fruit in pounds, p, are related by the equation c = 2.5p.

Which of the following is true about the proportional relationship?

a. The cost increases by $1 for every increase of 2.5 pounds.

b. The cost increases $2 for every half-pound increase in weight.

c. The cost increases by $2.50 for every 1-pound increase in weight.

d. There is not enough information to determine how the cost will increase.

Answer: c) The cost increases by $2.50 for every 1-pound increase in weight.