1. Problem of the Day
At a concession stand, hamburgers are selling at a rate of 160 hamburgers per hour. The table shows the rate at which wraps are selling.
Minutes 1 2 3 4
Wraps Sold
2.5 5
7.5 10
Concession Sales
a. Do hamburgers or wraps sell faster? Explain.
b. Graph equations that represent the growth rates of hamburgers sold and wraps sold in the same coordinate plane. Compare the steepness of the graphs. What does this mean in the context of the problem?
Items Sold
Minutes

3. Proportional Relationships Also called the constant of proportionality
A.K.A Direct Variation
When a straight line goes through (0,0), it has a proportional relationship
Origin
The constant of variation is _______________
The slope
Also called the constant of proportionality
y = constant x (y=kx)
The equation looks like ___________________

4. Proportional Relationships
The slope is ____________________
The rate of change
Constant ____________
Equation _____________
Using k, write a proportion to find y when x = 24

5. Is this a proportional relationship?
CoCo
Puffs
Marsh-mallows
General Mills is coming out with a new cereal called Hot Cocoa. They experimented with some samples to decide their recipe. We will chart to samples.
What is the CONSTANT?
How do you know?
240
342
What would the equation be?

6. Or check if the values form a proportion
Identifying Direct Variation
You need two things
Or check if the values form a proportion
Constant
SLOPE
Origin (0,0)

7. If four Oreo cookies contain 220 calories
If four Oreo cookies contain 220 calories. How many calories would be consumed if you eat three?
Find the constant variation first.
  Write and use the equation to solve for three cookies.

9. Exit Ticket

10. Is this a proportional relationship? Explain your answer
Gallons of gas used
Miles
driven 2 56 3 84 4
100 5
128 6
154
Is this a proportional relationship? Explain your answer