What type of relationship has a constant ratio between two quantities?
Proportional Relationship
How do you find the constant of proportionality?
What variable do we to represent it?
y/x
Variable 'k'
In order to convert different units of measurements, we need to set up a ____________, cross _________, and ____________.
Proportion, Multiply, Solve

Does this graph represent a proportional relationship? Explain why or why not.
No, because if a graph starts at anywhere other than the origin (0,0), it is not proportional.
If five movie tickets to see the new Marvel movie cost $60. How much would it cost for seven movie tickets?
$84
Describe the the two features that determine if a graph represents a proportional relationship.
1. Straight line
2. Begins at the origin (0,0)
What is the constant of proportionality in the following equations.
1. y=5x
2. y=3/4x
3. y=12x
1. k=5
2. k=3/4
3. k=12
7 inches = ________ centimeters
Use your reference sheet. Round to the nearest tenth.
17.8 cm
If a graph, where x represents the number of Starbucks Refreshers purchased, and y represents the total cost. What would the point (3, 15.75) represent? How much would each refresher cost?
3 Starbucks Refreshers cost a total of $15.75.
Each refresher cost $5.25
If two shirts at target cost $32, how much would five shirts cost?
$80
Do the following equations represent a proportional relationships? Explain.
1. y = 5x
2. y= 4x+2
3. y=-1/2x
1. Yes, the equation is written in the form y=kx.
2. No, the equation is not written in the form y=kx.
3. Yes, the equation is written in the form y=kx.

Find the constant of proportionality. (k)
Write the equation of the proportional relationship.
k= 13
y=13x
25 kilograms = _________ pounds
Use your reference sheet. Round to the nearest tenth.
55.1 lbs
If the equation is y = 2x, name two points on the graph.
Possible answers: (1,2) (2,4) (3,6) (4,8) (5,10)...
A Crumbl cookie recipe calls for 8 cups of flour for every 12 cup of sugar. How much flour would they use for 38 cups of sugar.
*Round to the nearest tenth.
25.3 cups of flour
If a table shows the values (2, 4), (3, 6), and (4, 8), do these quantities demonstrate a proportional relationship? Explain.
Yes, because they all have a constant ratio of 2 between the quantities.
Find the constant of proportionality. (k)
Write the equation of the proportional relationship.
k= 2
y= 2x
18 gallons = _________ liters
Use your reference sheet. Round to the nearest tenth.
68.2 L
Graph the proportional relationship.
y=4x
*Hint: Create a chart of x and y values.
Graph will be reviewed on white board.
Amanda's car uses 15 gallons of gas to travel 645 miles. How many kilometer can she travel?
Round to nearest whole kilometer.
1,038 km
A recipe calls for 3 cups of flour for every 2 cups of sugar. Is this a proportional relationship? Justify your answer.
No matter how much you scale the recipe up or down, the ratio stays the same.
Because the ratio between the two quantities does not change, the relationship is proportional.
At Krispy Kreme, for each dozen donuts sold, the price increases by $15.
Write an equation to represent the cost (y) of each donut (x) .
Using this equation, how much would it cost to buy 18 donuts?
y= 1.25x
$22.50 for 18 donuts.
20 liters = _______ quarts
*Hint: liters to gallons, gallons to quarts
Use your reference sheet. Round to the nearest tenth.
21.1 qts
Graph the proportional relationship.
y=1/2x
*Hint: Create a chart of x and y values.
Graph will be reviewed on white board.
If Kyle ran 3 miles in 40 min and Nick ran 4 kilometers in 40 minutes. Who ran a faster rate?
Kyle, because he ran a further distance in the 40 minutes.