MJ3 - Davidsen Middle School
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Transcript MJ3 - Davidsen Middle School
MJ3
Ch 5.1 – Ratios & Percents
Bellwork
1. Express the ratio 6 cups to 3 quarts in
simplest form.
2. Express 400 meters in 16 minutes as a
unit rate.
3. A 10-foot wall casts a 15-foot shadow.
How tall is a nearby tree that casts a 45foot shadow?
Note: You do not have to write the
questions
Assignment Review
Before we begin….
Please take out your notebook and get
ready to work….
Building upon what we have learned
about ratios…today we will look at
percents, which is a type of ratio….
Objective
Students will write ratios as percents
and vice versa.
Vocabulary
Percent – A percent is a ratio that
compares a number to 100.
Example
27 out of 100 can be written as
27 = 27%
100
The symbol % means percent
Writing ratios as percents
To write a ratio as a percent given a
verbal phrase, just place the number
over 100.
Example – According to the 2000 U.S.
Census, 22 out of ever 100 people living
in West Virginia were younger than 18.
22 out of 100 = 22%
Your Turn
In the notes section of you notebook
write the verbal phrases as percents.
1. During his baseball career, Babe Ruth
had a base hit about 34 out of every
100 times he came to bat.
2. In a recent year, 41.5 out of 100
households in the United States had
access to the Internet
Writing Ratios and Fractions as Percents
You can write a ratio or fraction as a
percent by converting the ratio or
fraction to and equivalent fraction with a
denominator of 100
Example:
1
=
20 =
20%
5
100
Your Turn
In the notes section of your notebook
write the following as equivalent
fractions with a denominator of 100.
Then calculate the percent.
1. 3 out of 5
2. 1 out of 4
Using a Calculator
You can also use a calculator to calculate
percent.
Let’s do this together….
Using the fraction 9/20
1.
2.
3.
4.
Input the 9 into your calculator
Press the divide button
Input the 20 into the calculator
Press the % key….
Caution: If you press the = key you will have
to convert the number to a percent!
Your Turn
Use you calculator to convert the
following ratios and fractions to a
percent
1. 3:5
2. 17:20
3. 17
50
Writing Percents as fractions
You can write a percent as a fraction by
placing the percent over 100 and
simplifying.
Example
30% =
30
=
3
100
10
24% =
24
=
6
100
25
Your Turn
In the notes section of your notebook
write the following percents as
fractions in simplest form
1. 29%
2. 43%
3. 40%
Summary
In the notes section of your notebook
summarize the key concepts covered in
today’s lesson
Today we discussed
Writing
ratios and fractions as percents
Writing percents as fractions in simplest
form
Assignment
Practice skills workbook lesson 5.1
This assignment is due tomorrow
You may use a calculator
I will grade this assignment