The Constant of Proportionality

Focus Questions:

• What is the relationship between the constant of proportionality and a unit rate?
• How do we determine the constant of proportionality from a table, equation, or graph?
• How do we represent proportional relationships using an equation?

Do Now:

Which pizzeria is the best buy?  How do you know?

Who is the fastest runner?  How do you know?

Part 1:  Connecting Unit Rates and the Constant of Proportionality

The constant of proportionality is another name used to describe the constant ratio that exists between two different quantities.  In all cases, this is the same as the ratio expressed in lowest terms. In most cases, this is the same as the "unit rate".

Look back on your work from last class, "The Four Pizzerias" and determine the equation to find the Total Cost at each pizzeria.

Notice that each equation has a constant multiplier that we had previously identified as the unit rate.  This is also known as the "constant of proportionality"

Part 2:  Determining and Using the Constant of Proportionality

As a group, work through the "Constant of Proportionality" assignment that you will be given in class.  If you get stuck, look through your notes or ask for help.

What you MUST do for next class:

• Complete the "Constant of Proportionality" assignment handed out in class.
• Complete the "Constant of Proportionality" assignment on Math XL For School