Ratios
What is a ratio?
A comparison of two quantities using division.
What is a proportion?
An equation that states that two ratios are equal.
How can ratios be used in real life?
Ratios can be used to compare quantities, like ingredients in recipes or distances in maps.
How do you simplify a ratio?
Divide both terms of the ratio by their greatest common factor (GCF)
How can you determine if two ratios are proportional?
Cross-multiply and see if the products are equal.
Find the constant (k) by dividing Y/X
Give an example of a proportion in a recipe.
If a recipe calls for 2 cups of flour for every 3 cups of sugar, that's a proportion.
If a recipe calls for 2 cups of flour to 3 cups of sugar, what is the ratio of flour to sugar?
The ratio is 2:3
If 3/4 of a pizza is left and you eat 1/4, how much is left?
1/2 of the pizza is left.
How would you use ratios to compare two different-sized pizzas?
Calculate the area of each pizza and compare the ratios of their areas.
If the ratio of cats to dogs is 4:5, how many cats are there if there are 20 dogs?
There are 16 cats.
If 2/5 of a class are girls and there are 20 students, how many girls are there?
There are 8 girls.
If a car travels 300 miles on 10 gallons of gas, what is the ratio of miles per gallon?
The ratio is 30 miles per gallon.
Create a ratio that relates 12 apples to 30 oranges.
The ratio is 2:5 (when simplified).
Solve for x: If 3/4 = x/16, what is x?
x = 12
Create a word problem that involves a proportion.
If 4 oranges cost $2, how much do 12 oranges cost? (Answer: $6)