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Proportions. Proportions. Proportions are similar to ratio except we already have the comparisons. With Proportions we tell whether to ratio are either equal, greater, or we can even solve using proportions. Solving Proportions. If we are solving we use what technique?
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Proportions • Proportions are similar to ratio except we already have the comparisons. • With Proportions we tell whether to ratio are either equal, greater, or we can even solve using proportions.
Solving Proportions • If we are solving we use what technique? • When solving we use the process of cross-multipliciation.
2. 50 z = = 20 16 n 9 = 3 4 3. n 12 z 40 = for Example 1 GUIDED PRACTICE Solve the proportion.
4. 25 t = 3 51 425 t = for Example 1 GUIDED PRACTICE
Rhinoceros Beetles An adult rhinoceros beetle weighs only 0.525ounce but can carry about 446.25ounces on its back. If a person were proportionately as strong as a rhinoceros beetle, how much weight could a 100 pound person carry? EXAMPLE 1 Writing and Solving a Proportion
ANSWER If human strength were proportional to that of a rhinoceros beetle, a 100 pound person could carry 85,000pounds. Write a proportion pounds . = = pounds 100 = 100 446.25 446.25 x x 85,000 x = ounces 100 100 0.525 0.525 ounces EXAMPLE 1 Writing and Solving a Proportion SOLUTION Use a table to set up a proportion. Multiply each side by 100. Simplify.
What If? . 1 Some ants weigh only 0.0001ounce but can carry about 0.005 ounce. If a person were proportionately as strong as one of these ants, how much weight could a 100 pound person carry? ANSWER If human strength were proportional to that of an ant, a 100 pound person could carry 5000pounds. for Example 1 GUIDED PRACTICE
Leap • 1. In Coach Lewis’s math class they are 15 boys in a class of 34. If we use this same ratio how many boys does coach Lewis teach out of 130 kids. • 2. The Central Middle School softball team has won 13 games out of 18. If they keep the same pace how many games will they play in order to win 15 more games.