150 likes | 382 Views
Setting Up a Proportion. SPI 6.1.1 Predictions & Conjectures SPI 6.2.6 Rates & Percents. What is a proportion?. A proportion is 2 equivalent ratios. Example : 6 = 3 20 10 What is a ratio? A ratio is a comparison of two numbers by division.
E N D
Setting Up a Proportion SPI 6.1.1 Predictions & Conjectures SPI 6.2.6 Rates & Percents
What is a proportion? • A proportion is 2 equivalent ratios. Example: 6 = 3 20 10 What is a ratio? • A ratio is a comparison of two numbers by division. Example: 6 black socks to a total of 20 socks
Using Proportions to solve Predictions • Out of the 32 students in a health class, 24 prefer using gel toothpaste. Based on these results, how many of 500 students in the school can be expected to prefer using gel toothpaste? Ratio: prefer gel toothpaste total students in class PART TOTAL Answer: 375 students out of 500 prefer gel toothpaste
Using Proportions to solve Ratios • At West Boulevard Middle School, the teacher to student ratio is 3 to 78. If there are 468 students enrolled at the school, how many teachers are there at the school? Answer: 18 teachers to 468 students
Proportions to solve Percent of a Number • The Mooney High School football team won 75% of their football games. If they played 12 games, how many did they win? Answer: won 9 games out of 12 total games
Setting Up a Proportion • Suppose you buy 2 CDs for $21.99. How many CDs can you buy for $65.97? Answer: 6 CDs for $65.97
Using Proportions to solve Discounts • A skateboard is on sale for 85% of the regular price. If it is regularly priced at $40, how much is the sale price? • How much is the discount? Answer: $34 sale price Answer: $6 discount
Using a Proportion to solve Unit Rate • If you work 22 hours a week and earn $139.70, how much money do you earn per hour? Answer: You earn $6.35 every hour
Proportions to solve Percent of a Number • Chad and Alisa donated 30% of their book collection to a local children’s hospital. If they had 180 books, how many did they donate to the hospital? Answer: 54 children's books out of 180 books total
Proportions to solve Probability Lorenzo asked every tenth student who walked into school to name their favorite pizza topping. • What is the probability that a student will prefer pepperoni pizza? • There are 384 students at the school Lorenzo attends. Predict how many students prefer pepperoni pizzas. Answer: 18/32 Answer: 216 prefer pepperoni pizzas
Proportions to solve Predictions • Use the results shown to predict the number of people out of 300 that would prefer vanilla ice cream? Answer: 135 prefer vanilla ice cream
Using Proportions to solve Discounts • The regular price of a pair of sneakers is $40. The sale price is 17% off the regular price. What is the sale price? Answer: The sales price of the sneakers is $33.20