Digits, Grade 7, Volume 1, Homework Helper

Unit D: Proportionality

Topic 6: Ratios and Rates

6-1: Equivalent Ratios

Part 1

Intro

A ratio is a relationship in which for every x units of one quantity there are y units of another quantity. The quantities x and y are the terms of the ratio.

Two circles and one square.

You use ratios to make comparisons. The ratio of the number of circles of the number of squares can be written in three ways.

table with 1 row and 3 columns , row1 column 1 , 2 to 1 , column 2 2 colon 1 , column 3 2 over 1 , end table

Example Writing Equivalent Ratios in Three Ways

Write each ratio in three ways.

Nine pool table balls: #2 blue, #10 blue striped, #6 green, #11 yellow striped, #14 green striped, #7 red, #12 purple striped, #4 purple, #15 red striped.

  • a. the number of solid-colored balls to the number of striped balls

  • b. the number of even-numbered balls to the number of odd-numbered balls

Solution

  • a. There are 4 solid-colored balls and 5 striped balls. The ratio of the number of solid-colored balls to the number of striped balls is 4 to 5, 4 : 5, or 4 fifths , .

  • b. There are 6 even-numbered balls and 3 odd-numbered balls. The ratio of the number of even-numbered balls to the number of odd-numbered balls is 6 to 3, 6 : 3, or 6 thirds , .


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Table of Contents

Digits, Grade 7, Volume 1, Homework Helper Unit A: Number and Operations Unit B: Expressions, Equations, and Relationships Unit C: Measurement and Geometry Unit D: Proportionality English/Spanish Glossary Formulas Math Symbols Formulas Measures Properties