6.RP.A.3. - Use ratios and rate reasoning to solve real-world and mathematical problems, e.g., by reasoning about tables of equivalent ratios, tape diagrams, double number line diagrams, or equations.
6.RP.A.3c - Find a percent of a quantity as a rate per 100 (e.g., 30% of a quantity means 30/100 times the quantity); solve problems involving finding the whole, given a part and the percent.
Lesson 5.1 - Investigate: Model Percents
Lesson 5.2 - Write Percents as Fractions and Decimals
Lesson 5.3 - Write Fractions and Decimals as Percents
Lesson 5.4 - Percent of a Quantity
Lesson 5.5 - Problem Solving: Percents
Lesson 5.6 - Find the Whole from a Percent