1. Math- Rates and Ratios
May 27,2014

2. Now, on to proportions! What is a proportion?
A proportion is an equation that equates two ratios
The ratio of dogs and cats was 3/2
The ratio of dogs and cats now is 6/4=3/2
So we have a proportion :

3. Properties of a proportion?
Cross Product Property
3x4 = 12
2x6=12
3x4 = 2x6

4. Properties of a proportion?
Cross Product Property
ad = bc
means
extremes

5. Properties of a proportion?
Let’s make sense of the Cross Product Property…
For any numbers a, b, c, d:

6. Properties of a proportion?
Reciprocal Property If
Can you see it?
If yes, can you think of why it works?
Then

7. How about an example? 7(6) = 2x 42 = 2x 21 = x Solve for x:
Cross Product Property

8. How about another example?
Solve for x:
7x = 2(12)
7x = 24
x =
Cross Product Property
Can you solve it using Reciprocal Property? If yes, would it be easier?

9. Percent proportion
What is a percent proportion?
Learn zillion

10. Let’s practice The Percent Proportion
A percent is a ratio that compares a number to 100. To write a percent as a fraction, express the ratio as a fraction with a denominator of 100. Fractions should be stated in simplest form.

12. In a comparison taste test of two drinks, 780 students preferred Berry Blast. Only 220 students preferred Melon Splash.
A) There were ___ more people who preferred Berry Blast.
B) In the taste test ____ % of the people preferred Berry Blast.
C) People who preferred Berry Blast out numbered people who preferred melon Splash by a ratio of ___ to __

13. How many jumps does it take?
Ladder Method 1 2 3
KILO 1000 Units
HECTO 100 Units
DEKA 10 Units
DECI 0.1 Unit
Meters Liters Grams
CENTI 0.01 Unit
MILLI Unit
How do you use the “ladder” method?
1st – Determine your starting point.
2nd – Count the “jumps” to your ending point.
3rd – Move the decimal the same number of jumps in the same direction.
King Henry Died Drinking Chocolate Milk
4 km = _________ m
Starting Point
Ending Point
How many jumps does it take? 4. 1
__. 2
__. 3
__.
= 4000 m