Question

This graph shows a proportional relationship.

What is the constant of proportionality?

Enter your answer in the box.

A coordinate plane showing the first quadrant only with the title Amount Earned vs. Time Worked. The x axis is labeled Time in hours. It extends from 0 to 15 in increments of 1 hour. The y axis is labeled Earnings in dollars. It extends from 0 to 90 in increments of 5 dollars. A line passes through the origin and the following points. Begin ordered pair 3 comma 36 end ordered pair. Begin ordered pair 5 comma 60 end ordered pair. Begin ordered pair 6 comma 72 end ordered pair. Begin ordered pair 7 comma 84 end ordered pair.

Answer 1

• k = 12

Explanation:

One pair of coordinates is sufficient to work out the constant of proportionality.

Equation in general form:

• y = kx

and

• Point (3, 36)

Substitute x- and y- coordinates into equation and find the value of k:

• 36 = k*3
• k = 36/3
• k = 12