Explore – Mini-Lesson
Let’s learn about a helpful tool for ratio problems that
could help you with all sorts of ratio problems.
Example 1) The ratio of boys to girls in a class is 2 to 3.
1. If there are 4 boys in the class, how many girls are
there?
Agenda
1
Explore – Mini-Lesson
New Tool: Tape Diagram
We can use a tape diagram to solve ratio math problems.
Example 1) The ratio of boys to girls in a class is 2 to 3.
boys
girls
Each box represents a
number in the original
ratio.
1. If there are 4 boys in the class, how many girls are
there?
Now let’s look at the question.
Agenda
2
Explore – Mini-Lesson
New Tool: Tape Diagram
We can use a tape diagram to solve ratio math problems.
Example 1) The ratio of boys to girls in a class is 2 to 3.
boys
If this tape shows 4
boys then…
girls
1. If there are 4 boys in the class, how many girls are
there?
Agenda
3
Explore – Mini-Lesson
New Tool: Tape Diagram
We can use a tape diagram to solve ratio math problems.
Example 1) The ratio of boys to girls in a class is 2 to 3.
4
boys
girls
2
2
This tape
How
manyisstudents
4 boys.
arewe
So
in one
put 4box?
above
the tape.
2
1. If there are 4 boys in the class, how many girls are
there?
Agenda
4
Explore – Mini-Lesson
New Tool: Tape Diagram
We can use a tape diagram to solve ratio math problems.
Example 1) The ratio of boys to girls in a class is 2 to 3.
4
boys
girls
2
2
2
2
?
2
Rule:
We Important
don’t yet
know
Thethe
number
in each
number
of box
girlsmust
be the same for every tape.
so we put a ? for the
length of that tape.
1. If there are 4 boys in the class, how many girls are
there?
Agenda
5
Explore – Mini-Lesson
New Tool: Tape Diagram
We can use a tape diagram to solve ratio math problems.
Example 1) The ratio of boys to girls in a class is 2 to 3.
4
boys
girls
2
2
2
2
?
2
Now we can answer
the question.
1. If there are 4 boys in the class, how many girls are
there?
6
Agenda
6
Explore – Mini-Lesson
New Tool: Tape Diagram
Let’s try another one.
Example 2) The ratio of boys to girls in a class is 3 to 2.
?
We can label what we
First,
the tapes.
know.draw
8 girls.
boys
We can put a question
girls
mark for what we
8
don’t know.
2. If there are 8 girls in the class, how many boys are
there?
Now let’s look at the question.
Agenda
7
Explore – Mini-Lesson
New Tool: Tape Diagram
Let’s try another one.
Example 2) The ratio of boys to girls in a class is 3 to 2.
?
boys
girls
4
4
8
How many students
does
each box
This makes
8 girls.
represent? 4
2. If there are 8 girls in the class, how many boys are
there?
Agenda
8
Explore – Mini-Lesson
New Tool: Tape Diagram
Let’s try another one.
Example 2) The ratio of boys to girls in a class is 3 to 2.
?
boys
4
4
girls
4
4
8
4
Remember:
Every box must have
the same quantity.
2. If there are 8 girls in the class, how many boys are
there?
Can you answer the question using
12 the diagram?
Advanced: Think of one way you could prove that the
numbers in each box should be 4. Tell your partner.
9
Agenda
Tape Diagram with Fractions
• Matthew has 14 blue marbles. His blue
marbles make up two-fifths of his total
number of marbles. How many marbles does
Matthew have?