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RATIO |
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Objective: |
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The student will be able to solve problems involving ratios |
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Standards: |
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7.4 Proportionality. The student applies mathematical process standards to represent and solve problems involving proportional relationships. The student is expected to:
(D) solve problems involving ratios, rates, and percents, including multi-step problems involving percent increase and percent decrease, and financial literacy problems |
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Success Criteria: |
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Understand and use ratios in mathematical applications of daily life. |
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Definition: |
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A ratio is a numerical comparison of 2 or more quantities to compare their relative sizes. A ratio is often denoted by a:b which is said “a to b”, meaning that by every a units of one quantity there are b units of the other. |
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Mini Lesson: |
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In a farm, there are 5 roosters and 40 hens.
The ratio from roosters to hens is 5 to 40 (or 5:40).
A common way to write a ratio is as a fraction. As a fraction, this is ratio can be written as 5/40. This fraction can be simplified to 1/8 (5/40=1/8). So, instead of comparing 5 to 40, we can divide numerator and denominator by 5 to get a ratio of 1 to 8. For every roster, there are eight hens.
There is one roster per eight hens (the "per" word instantly indicates a ratio). |
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Ratios in Daily Life: |
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The ratio of boys to girls in our classroom is 3:4
The student correctly answered 36 of the 40 questions (36:40, 36/40=9/10).
Two parts of white paint to one part of blue paint (2:1)
18 pesos per dollar (18:1) [currency exchange]
The ratio of raisins to chocolate chips in one cookie is 4:6 (4/6=2/3) |
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Vocabulary: |
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Ratio: is a comparison of two quantities.
Equivalent ratios: are ratios that show the same relationship between the two quantities (they have the same numerical value). |
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Resources: (from MsGarciaMath) |
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Ratio Concept VIDEO |
Ratio Concept VIDEO |
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Ratio Help |
Ratio Help |
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Greatest Common Factor (GCF) |
Greatest Common Factor (GCF) |
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Simplify a fraction using GCF |
Simplify a fraction using GCF |
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Simplify Fractions |
Simplify Fractions |
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Find The Prime Factors |
Find The Prime Factors |
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Example Problems: |
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There are twelve girls and nine boys in or classroom. What is the ratio of girls to boys? |
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This year the basketball team of the school played eight games and won five. What is the ratio of the games that they do not win, to the games played? |
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The ratio of boys to girls in our classroom is 3:4 and there are 28 students in our class, how many students in the class are boys and how many are girls? |
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In a class of 20 students, 4 students failed the math exam. What is the ratio of students who passed to the total number of students? Write this as a ratio in the simplest form (using a fraction, a colon and the word to). |
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The ratio of boys to girls in our school is 2:3. There are 448 boys, find the number of girls and the total number of students. |
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