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Write two fractions equivalent to 4/5 When am I going to use this?

Learn how to use proportions to find unknown values, equivalent ratios, and missing parts. Practice solving problems using cross products, decimals, and algebraic methods.

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Write two fractions equivalent to 4/5 When am I going to use this?

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  1. How do you use proportions to find unknown values? 706.2.7 Use ratios and proportions to solve problems • Write two fractions equivalent to 4/5 When am I going to use this? Heath needs 1/3 cups of sugar for 1 batch of cookies. How much would he need for 4 batches?

  2. Proportions How to check if two ratios are Proportions Finding the missing number Using equivalent ratios Finding the missing number Using algebra Finding the missing number Using cross products

  3. Proportions How to check if two ratios are proportions 1. Turn both ratios into decimals 2. Simplify both ratios: They should simplify to the same ratio if they are equal 3. Cross Multiply from bottom to top: The products should be the same if they are equal

  4. Simplify to check Use cross products Use decimals to check

  5. Assessment Prompt • Use all 3 methods to determine if the following are proportions. • 5/4 = 20/12 • 7/9 = 49/63 • 15/25 = 21/35

  6. Proportions How to check if two ratios are proportions How to find the missing part of a proportion using equivalent ratios Step 1: Reduce the fraction you have. Then see how you can multiply from one fraction to the other.

  7. Proportions How to find the missing part of a proportion using (algebra) Step 1: Cross Multiply 24/36 = 10/x Step 2: Isolate the variable by doing the opposite operation to both sides. Step 3: Simplify your fraction

  8. Proportions How to check if two ratios are proportions How to find the missing part of a proportion using (cross products) Easy Using cross products is algebra.

  9. Short Cut for Solving Proportions • If the numerator is missing: Multiply the denominator of the missing numerator by the fraction: your answer is the missing numerator. x/4 = 9/12 = 9/12 * 4 = 3 • If the denominator is missing: multiply the numerator of the missing denominator by the reciprocal of the fraction. 3/x = 9/12 = 12/9 * 3 = 4

  10. Assessment Prompt • Solve the following proportion using 2 methods. • 8/12 = x/36

  11. Homework: • Workbook pg. 73-74

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