Solving Proportions

 Ratios: A comparison of two numbers using division.  Three ways to write Ratios:  a to b  a : b ,where b is not 0  Proportion: An equation of the form that states that two ratios are equivalent.

Steps: 1. Set up proportion. Make sure the ratios match. (Top matches top and bottom matches bottom) 2. Cross Multiply and Divide.

#1 Luke bought a dozen daisies for $4.20. What is the price of 2 daisies?

#2 The ratio of students to teachers at Orchard Elementary School is 45 to 3. If there are 315 students, how many teachers are there?

#3 Emmanuel can run 100 meters in 20 seconds. If he competes in the 400-meter race, how many seconds will it take him to run the race at the same rate?

#4 Patrick drew a map of his neighborhood. He used a scale in which 1 inch equals 2 miles. What distance on Patrick’s map should represent the 1.5 miles between his house and the nearest gas station?

#5 An athlete on the school football team can run 20 yards in 2.9 seconds. During the last football game, the athlete ran 64 yards for a touchdown. If the athlete’s rate of speed remained the same, how long did I take him to run for the touchdown?

#6 A recipe that makes 18 cookies calls for 3/4 cup of sugar. How much sugar is needed to make 24 cookies using this recipe?

#7 Mrs. Johnson’s 2 nd block class has 10 girls and 12 boys. How many girls would be in Mrs. Johnson’s class if there were 36 boys?

#8 Janie’s Triple Fudge Cake calls for 3 cups of flour and 4 cups of sugar. How many cups of sugar would be needed if Janie decides to use 10.5 cups of flour?

#9 Seven movie tickets cost $ How much would 15 movie tickets cost?