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Percent Proportions. Using Proportions 4-1. Vocabulary Review. Ratio: The comparison of two numbers (written in Algebra as a fraction) Proportion: When two ratios are equal to each other Cross Product(s):
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Percent Proportions Using Proportions 4-1
Vocabulary Review Ratio: The comparison of two numbers (written in Algebra as a fraction) Proportion: When two ratios are equal to each other Cross Product(s): When we cross multiply/compare diagonally, the special relationship between two ratios in a proportion
Percent Proportions Proportions can be used to solve missing percentages of a number… “is #” = given/missing % “of #” 100%
Percent Proportions We use the same steps to solve… Cross multiply Cross multiply Divide to solve Ex. Find 30% of 24. Is # = Of # = Given/missing % = Write out proportion… x = 30% 24 100% *Round answer to nearest tenth of percent! Ex. What percent is 20 of 210? Is # = Of # = Given/missing % = Write out proportion… = 100% *Round answer to nearest tenth of percent!
Percent Proportions Ex. What is 33 1/3% of 150? x = 33.3% 150 100% Ex. 5 is 80% of what number? 5 = 80% x 100%
Practice • 6% of what number is 2.46 • What percent of 72 is 27? • Find 72% of 310.
Homework p. 161 #9-20 all (Calculator okay!) Show set up/process/work