Transcript Ratios - SchoolFusion

LESSON 6-1
Warm Up
Lesson 6-1 Warm-Up
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LESSON 6-1
Warm Up
Lesson 6-1 Warm-Up
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“Ratios” (6-1)
What is a “ratio”?
Ratio: a comparison of two numbers by division – There are three ways
to compare two numbers:
a
a to b
a:b
b
read as “to”
How do you write a
ratio?
You can write a ratio to compare a part to a part or part to a whole. The
first item being compared is always the first number and the second item
being compared is the second number of the ratio.
Example: A recipe calls for 4 cups of cereal and 2 cups of pretzels.
Write this as a ratio.
What are “equivalent
ratios”?
Equivalent Ratios: two ratios that name the same comparison or
relationship to one another
4
1
Example:
=
; 4 to 8 = 1 to 2 ; 4:8 = 1:2
8
2
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Ratios
LESSON 6-1
Additional Examples
During a school trip, there are 3 teachers and
25 students on each bus. Write the ratio of teachers to
students in three ways.
There are 3 teachers and 25 students.
teachers to students
3 to 25 or 3 : 25 or 3
25
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“Ratios” (6-1)
How do you find
equivalent ratios?
You can find equivalent ratios the the same way you find equivalent
fractions. Multiply or divide each part of the ratio by the same number.
Example: Write two different ratios equivalent to 4:6.
How do you write a
ratio in simplest form?
You can simplify a ratio the same way you simplify a fraction. Divide both
numbers by the greatest common divisor (GCD) or by common divisors
(factors) until you can’t divide anymore.
Example: Write the ratio of bats to balls in simplest form.
There are 8 bats and 12 balls, so the ratio of bats to balls is 8:12.
The ratio of bats to ball is 2:3 (meaning for every 2 bats, there are 3
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balls).
Ratios
LESSON 6-1
Additional Examples
Write two different ratios equivalent to 24 : 8.
24 : 8
Divide each
term by 8.
÷8
24 : 8
÷8 ÷2
3:1
÷2
Divide each
term by 2.
12 : 4
Two ratios equal to 24 : 8 are 3 : 1 and 12 : 4.
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Ratios
LESSON 6-1
Additional Examples
Write each ratio in simplest form.
a. 121 to 11
121 to 11
÷ 11
÷ 11
11 to 1
In simplest form, the ratio 121 to 11 is 11 to 1.
b. 28 : 16
28 : 16
÷4
÷4
7:4
In simplest form, the ratio 28 : 16 is 7 : 4.
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Ratios
LESSON 6-1
Lesson Quiz
A drama club has 14 females and 8 males. For questions
1 and 2, write each ratio in three ways.
1. males to females
8
8 to 14, 8 : 14,
14
2. females to males
14 to 8, 14 : 8,
14
8
3. Write two different ratios equivalent to 4 : 8.
Sample answer: 1 : 2; 5 : 10
Write each ratio in simplest form.
4. 8
12
2
3
5. 10 : 6
5:3
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