Proportional
What two things must be true for a graph to be proportional?
The line must be straight. It must go through the origin.
What do you use to help you solve unit rate problems?
Double Number Lines
When applying a discount do you add or subtract from the original price?
Subtract
When applying a tax or tip, do you add or subtract from the original price?
Add
k = y/x
If a recipe calls for 3 cups of flour and 1/2 cup of butter, how much flour would you use for 1 cup of butter?
6 cups of flour
Price: $45.99
Discount: 25% off
$34.49
Price: $25
Tip: 20%
$30
How do you determine if a table is proportional or not?
Find the constant of proportionality (k) for every point. If they are all the same then it is proportional.
You can read 1/4 of a book in 1/6 of an hour. How much of the book can you read per hour?
6/4 or 1 1/2 of a book per hour
Price: $199
Discount: 17%
$165.17
Price: $99.99
Tax: 10%
$109.99
Is the table below proportional?
X| 2| 3| 4|
Y| 6| 9| 12|
Yes, k = 3.
You need 1 2/3 cup of water and 2 cups of lemon juice for make lemonade. How much lemon juice would you need if you only use 1 cup of water?
6/5 or 1 1/5 of lemon juice
A pair of shoes costs $65.00. If you use a coupon for 35% off, how much is the sale price of the shoes?
$42.25
At a restaurant, dinner comes to a total of $105.20. You want to tip the server 18%. What is the total cost of the dinner?
$124.14
Is the table below proportional?
X| 1| 2 | 3 |
Y| 5| 10| 20|
No.
A recipe calls for 3 cups of milk and 2 1/4 cups of sugar. How much sugar would you need if you only use 1 cup of milk?
9/12 or 3/4 cups of sugar
A store is having a 30% of sale for Black Friday. If you buy a shirt for $25, how much will you save?
$7.50
At a store you buy headphones for $199.99 plus 7.25% tax. What is the sale price of the headphones?
$214.49