Lesson 5Defining Equivalent Ratios
Learning Goal
Let’s investigate equivalent ratios some more.
Learning Targets
If I have a ratio, I can create a new ratio that is equivalent to it.
If I have two ratios, I can decide whether they are equivalent to each other.
Lesson Terms
- equivalent ratios
Warm Up: Dots and Half Dots
Problem 1
Dot Pattern 1:
Dot Pattern 2:
Activity 1: Tuna Casserole
Here is a recipe for tuna casserole.
Ingredients
3 cups cooked elbow-shaped pasta
6 ounce can tuna, drained
10 ounce can cream of chicken soup
1 cup shredded cheddar cheese
cups French fried onions
Instructions
Combine the pasta, tuna, soup, and half of the cheese. Transfer into a 9-inch-by-18-inch baking dish. Put the remaining cheese on top. Bake 30 minutes at 350 degrees. During the last 5 minutes, add the French fried onions. Let sit for 10 minutes before serving.
Problem 1
What is the ratio of the ounces of soup to the cups of shredded cheese to the cups of pasta in one batch of casserole?
Problem 2
How much of each of these 3 ingredients would be needed to make:
twice the amount of casserole?
half the amount of casserole?
five times the amount of casserole?
one-fifth the amount of casserole?
Problem 3
What is the ratio of cups of pasta to ounces of tuna in one batch of casserole?
Problem 4
How many batches of casserole would you make if you used the following amounts of ingredients?
9 cups of pasta and 18 ounces of tuna?
36 ounces of tuna and 18 cups of pasta?
1 cup of pasta and 2 ounces of tuna?
Are you ready for more?
Problem 1
The recipe says to use a 9 inch by 18 inch baking dish. Determine the length and width of a baking dish with the same height that could hold:
Twice the amount of casserole
Half the amount of casserole
Five times the amount of casserole
One-fifth the amount of casserole
Activity 2: What Are Equivalent Ratios?
Problem 1
The ratios
Is the ratio
equivalent to these? Explain your reasoning. Is the ratio
equivalent to these? Explain your reasoning. Give two more examples of ratios that are equivalent to
. How do you know when ratios are equivalent and when they are not equivalent?
Write a definition of equivalent ratios.
Pause here so your teacher can review your work and assign you a ratio to use for your visual display.
Create a visual display that includes:
the title “Equivalent Ratios”
your best definition of equivalent ratios
the ratio your teacher assigned to you
at least two examples of ratios that are equivalent to your assigned ratio
an explanation of how you know these examples are equivalent
at least one example of a ratio that is not equivalent to your assigned ratio
an explanation of how you know this example is not equivalent
Be prepared to share your display with the class.
Lesson Summary
All ratios that are equivalent to
For example, the ratio
Is
No, because 18 is