1. EQ: How are proportions used to solve real-world problems?

2. Definition: Two equivalent (equal) ratios
What is a proportion?
Definition: Two equivalent (equal) ratios
2:3 as 6:9
2 is to 3 as 6 is to 9
Start Proportion Frayer GO with this slide.

3. Do 2 ratios form a proportion?
Cross-products
Scale factor
•3 =
•3 ≠
•3 =
•3 =
On GO
yes no
yes no

4. Review…
Proportional?

5. Proportional?

6. Is it a proportion?

7. Is it a proportion?

8. Think, Pair, Share
Tell your partner what x would be in this proportion:

9. How are proportions solved?
1) Reduce the fractions
Try on GO, then discuss reducing first.
2) Set the cross-products equal to each other
12 = 3x
4 = x

10. Try this one:

11. EQ: How are proportions used to solve real-world problems?
Day 2 starts here

12. 4in. per 10min. is to x in. per 20 min.
Proportion Problems
Example:
4in. per 10min. is to x in. per 20 min.
Be consistent in placing information!

13. Word Problems Make sure units match in the proportion
Again, be consistent in placing information
Solve by cross-multiplying

14. Let’s try it!!
A snowstorm dumped 18 inches of snow in a 12-hour period. How many inches were falling per hour?
9 = 6x
x = 1.5in