1 / 14

Proportions

Proportions. What is a Proportion?. An equation which shows two equivalent ratios. Why do we use Proportions?. They help us to find relationships in the real world which are similar. There are two methods to evaluate a proportion. Method 1 -- Scale Factor Method 2 -- Cross Products.

wenda
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

  2. What is a Proportion? • An equation which shows two equivalent ratios Why do we use Proportions? • They help us to find relationships in the real world which are similar

  3. There are two methods to evaluate a proportion • Method 1 -- Scale Factor • Method 2 -- Cross Products

  4. Scale Factor Method • Step 1 – Setup the Problem Julian is the best cake baker in Richmond. To make a cake, he uses 1 egg for every 2 cups of flour. If the recipe calls for 10 cups of flour, how many eggs does he need? Item Ratio

  5. Scale Factor Method • Step 2 – Find number (scale factor) that you can multiply by to get from side with two numbers to side with variable.

  6. Scale Factor Method • Step 2 – Find number (scale factor) that you can multiply by to get from side with two numbers to side with variable. x5 x5

  7. Scale Factor Method • Step 3 – Multiple to find the answer x5 x5 2 x 5 = 10 and 1 x 5 = 5; therefore, X = 5

  8. Cross Products Method • Step 1 – Setup the Problem Tom is driving to New York. He travels 70 miles every 2 hours. If the trip takes 8 hours, how many miles will he travel? Ratio

  9. Cross Products Method • Step 2 – Multiple numbers from top left to bottom right 70  8 = 560

  10. Cross Products Method • Step 3 - Multiply numbers from top right to bottom left 2 · x = 2x

  11. Cross Products Method • Step 4 - Write products as an equation 560=2x

  12. Cross Products Method • Step 5 – Divide by this number to get x by itself 560=2x

  13. Example Wendy works at a kennel. There are 3 cats for every 2 dogs. If she takes in 18 cats, how many dogs will she have? Ratio

  14. Example Simone is taking a trip to Florida for spring break. Her family travels 1250 miles in 25 hours. At their rate of travel, how many miles did they travel per hour?

More Related