1 / 12

Proportions

Proportions. 7 th Grade Math November, 2012. Proportions with Pandas. ..videosProportions with Pandas.asf. What is a Proportion?. A proportion is when two ratios or rates are equivalent! Example: ½ and 7/14 Why are these two proportional?

kaiyo
Download Presentation

Proportions

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

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

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

  9. Things to Remember… Beats =Beats Minutes Minutes • 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.

  10. You try… • 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?

  11. After Fall Break, start here. 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

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

More Related