Writing Equations for Proportional Relationships

This video tutorial teaches how to write an equation expressing the relationship between two proportional quantities by finding the constant of proportionality. It explains that if x and y are proportional, the equation y = kx can be used, where k is the constant found by dividing y by x. The video provides an example using feet and yards, demonstrating how to plot points on a graph and determine the constant proportionality, which is 3 in this case. The lesson concludes by reinforcing the concept of proportional relationships and their graphical representation as a straight line through the origin.

What is the general form of an equation that represents a proportional relationship between two quantities?

• y = x - k

• y = k + x

• y = kx

• y = x/k

How can you find the constant of proportionality in a proportional relationship?

• By subtracting x from y

• By dividing y by x

• By multiplying x and y

• By adding x and y

What is a key characteristic of the graph of a proportional relationship?

• It is a vertical line.

• It is a straight line through the origin.

• It is a curved line.

• It is a horizontal line.

In the example of feet and yards, what is the constant of proportionality?

• 2 feet per yard

• 3 feet per yard

• 5 feet per yard

• 4 feet per yard

What equation represents the relationship between feet and yards in the given example?

• y = 4x

• y = 3x

• y = 5x

• y = 2x