Proportions with Multiplicative Relationships
Proportions with the "Butterfly Method"
What's Missing?
(Part, Whole, or %)
Setting Up
% Proportions
Solving
% Proportions
100
8/x = 25/100
x=32
100
x/250 = 30/100
x=75
100
"Carl has 200 songs on his MP3 player. Of these songs, 24 are country songs. What percent of Carl's songs are country songs?" What's missing - part, whole, or percent?
Percent
100
Carl has 200 songs on his MP3 player. Of these songs, 24 are country songs. What percent of Carl's songs are country songs? SET UP THE PROPORTION!
24/200 = x/100
100
Carl has 200 songs on his MP3 player. Of these songs, 24 are country songs. What percent of Carl's songs are country songs? SOLVE!
12 songs
200
x/300 = 30/100
x=90
200
x/40 = 70/100
x=28
200
"Ashton is saving money to buy a new bike. He needs $120 but has only saved 60% so far. How much money has Ashton saved?" What's missing - part, whole, or percent?
Part
200
Ashton is saving money to buy a new bike. He needs $120 but has only saved 60% so far. How much money has Ashton saved? SET UP THE PROPORTION!
x/120 = 60/100
200
Ashton is saving money to buy a new bike. He needs $120 but has only saved 60% so far. How much money has Ashton saved? SOLVE!
$72
300
10/x = 40/100
x=25
300
x/150 = 24/100
x=36
300
"At a shelter, 15% of the dogs are puppies. There are 9 puppies. How many total dogs are at the shelter?" What's missing - part, whole, or percent?
Whole
300
At a shelter, 15% of the dogs are puppies. There are 9 puppies. How many total dogs are at the shelter? SET UP THE PROPORTION!
9/x = 15/100
300
At a shelter, 15% of the dogs are puppies. There are 9 puppies. How many total dogs are at the shelter? SOLVE!
60 dogs
400
7.5/10 = x/100
x=75%
400
12/80 = x/100
x=15%
400
"There are about 36 weeks in a school year. On January 14th, we will be 50% through the school year! How many weeks will have passed on January 14th?" What's missing - part, whole, or percent?
Part
400
There are about 36 weeks in a school year. On January 14th, we will be 50% through the school year! How many weeks will have passed on January 14th? SET UP THE PROPORTION!
x/36 = 50/100
400
There are about 36 weeks in a school year. On January 14th, we will be 50% through the school year! How many weeks will have passed on January 14th? SOLVE!
18 weeks
500
1.25/1 = x/100
x=125%
500
21/35 = x/100
x=60%
500
"Kassandra correctly answered 36 out of 40 questions on her test. What is her score out of 100?" What's missing - part, whole, or percent?
Percent
500
Kassandra correctly answered 36 out of 40 questions on her test. What is her score out of 100? SET UP THE PROPORTION!
36/40 = x/100
500
Kassandra correctly answered 36 out of 40 questions on her test. What is her score out of 100? SOLVE!
90%
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