A ratio can have equivalent ratios just like a fraction can have equivalent fractions.
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Transcript of A ratio can have equivalent ratios just like a fraction can have equivalent fractions.
If you know the ratio of students to teachers is 5 to 1 and you know there are 15 teachers, is there a way to figure out
the number of students?
In this lesson you will learn to solve for missing values in a ratio problem by setting up a
table.
Let’s Review
A ratio can have equivalent ratios just like a fraction can have equivalent
fractions.
2 : 1x3 x3 6 : 3
A Common Mistake
The ratio of students to teachers is 5 to 1. There are 15 teachers.
5 1
wrong column!
students teachers
15 ?
Core Lesson
Andy has a ratio of books to DVDS of 3 : 2 in his room. If he has 15 books, how many
DVDs does he have?
How can I use the ratio to help set up
and solve?
Core Lesson
Books to DVDs3 to 2
15 books? DVDS
Books DVDS3 2
6 49 6
12 815 10Andy has 15 books
and 10 DVDs.
+3 +2+3 +2+3 +2+3 +2
Core Lesson
+3+3+3+3
Books DVDS3 2
6 49 6
12 815 10
+2+2+2+2
x 5 x 5 multiplicative reasoning
additive reasoning
In this lesson you have learned to solve for missing values in a ratio problem by setting up a
table.
Guided Practice
Anita collects shells and stones in a ratio of 1 : 2. If she has a total of 8 shells, how many stones does she have?
Extension Activities
1students teachers
15 3 10
5
Fill in the missing values of the table.
Write a paragraph explaining what ratio properties were
used to create and fill in the table.
Extension ActivitiesAnnie bakes cookies and cupcakes in a ratio of 5 to 4 for her gift boxes. Her school needs 36 desserts to sell in a bake sale.
How many cupcakes will she bake?
How many cookies will she bake?
Create an illustration and a table to support your work.
Quick Quiz
George buys oranges and apples at a ratio of 2 :5 for his party. If he has 14 oranges, how many apples does he have?Kelly bakes cupcakes and cookies in a ratio of 5 to 3 for her bakery. If on any given day she bakes 18 cookies, how many cupcakes did she bake that day?