Math- Rates and Ratios May 27,2014

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 :

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

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

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

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

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

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?

Percent proportion What is a percent proportion? Learn zillion

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.

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 __

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 0.001 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