Presentation is loading. Please wait.

Presentation is loading. Please wait.

Proportions 7 th Grade Math November, 2012. Proportions with Pandas..\videos\Proportions with Pandas.asf.

Similar presentations


Presentation on theme: "Proportions 7 th Grade Math November, 2012. Proportions with Pandas..\videos\Proportions with Pandas.asf."— Presentation transcript:

1 Proportions 7 th Grade Math November, 2012

2 Proportions with Pandas..\videos\Proportions with Pandas.asf

3 What is a Proportion? A proportion is when two ratios or rates are equivalent! Example: ½ and 7/14 Why are these two proportional? You can also check using their “Cross Products” “Math Doesn’t Suck” – Page 211-212

4 What is a Proportion? In Notes, write “See Example Page in binder” Are the following ratios proportional? 2 adults to 10 children: 3 adults to 12 children 12 inches to 8 inches: 18 inches to 12 inches 8 feet to 21 seconds: 12 feet to 31.5 seconds $5.60 for 5 pairs of socks: $7.12 for 8 pairs of socks.

5 Compare and Contrast Write each rate as a fraction 1. If Mark drove 50 miles on 2 gallons of gas, what was his mileage rate? 2. If Alicia drove 75 miles on 3 gallons of gas, what was her mileage rate? 3. If I drove 12.5 miles on a half gallon of gas, what is my rate? What is different? What is the same? Find the unit rate for each one. What does this mean?

6 Solve using a method reasonable to you Tammy bought 3 widgets for $2.40. At the same price, how much would 10 widgets cost? Tammy bought 4 widgets for $3.75. How much would a dozen widgets cost? At the Office Super Store, you can buy plain #2 pencils, four for.59¢. The store also sells the same pencils in the large box of 5 dozen pencils for $7.79. How much do you save by buying the large box? The price of a box of 2 dozen candy bars is $4.80. Sam wants to buy 5 candy bars. What will he have to pay?

7 Two ways to solve proportions 1. 1. Compare Unit Rates 1. (Problems 1 and 2 on previous slide) 2. 2. Use Cross Products 1. (Problems 3 and 4 on previous slide) 3. We’ve talked about unit rates quite a bit (Remember our “Comparing Products” Activity) … 4. Let’s discuss “Cross Products” Start Here

8 Cross Products Study Jams Video: http://studyjams.scholastic.com/studyjams/jams/math/algeb ra/proportion.htm

9 Things to Remember… Keep the numerator and denominator units the same. (Label, Label, Label!) For example, If you are comparing heartbeats per minute in the first ratio, you must leave it as heartbeats per minute in the second ratio. Beats= Beats Minutes

10 1. 2. 3.4. 5. Solve the proportion. Mrs. Miller drove 203 miles in 3.5 hours. At this rate, how long will it take her to drive another 29 miles to the next town? You try…

11 Practice Glencoe Skills Practice – Lesson 6-6 Separate sheet of paper (show BOTH ratios and LABEL!) Independent Practice – In Class Page 313-314: #14, 16, 28-32, 35, 36, 41-43, 50 We will grade each other’s problems in 15 minutes. Homework: Glencoe Word Problems – Lesson 6-6 Glencoe Practice – Lesson 6-6 After Fall Break, start here.

12 Real World Examples “Proportions Gallery Walk” - PowerPoint – “Real World Proportions”


Download ppt "Proportions 7 th Grade Math November, 2012. Proportions with Pandas..\videos\Proportions with Pandas.asf."

Similar presentations


Ads by Google