## Tuesday, October 18, 2011

### Shera's Proportion Post

A ratio is a comparison of two quantities that have the same unit of measure.

Example:

A rate is a comparison of two quantities measured in different units. Example: \$1.69 per 100 grams or \$1.69/100g is a rate for purchasing bulk food. 72 beats per minute or 72 beats/min is a heart rate.

A proportion is an equation which states that two ratios are equal.

1. 5 hours to travel 360 miles is about 72 mph.

5/360 = 1/72

2. As a playgroup worker, if I increase the amount of apple juice I am serving at the playgroup from 25 ml to 100 ml, how much should I increase the orange juice to, to keep the quantities in the same proportion? The orange juice is 50 ml to start with.

What are the three ways you can prove that equivalent ratio statements are true?

3/4 = 12/16 or 4/9 = 16/32

3/4 = 12/16 is true.

Diagonal:

Horizontal:

1. Does this seem fair?

- No it does not.

2. With what you know about proportion look and read what is in the image above. Does it seem just and fair? Why have you made this choice?

- No it does not seem fair because Paul Allen stole 3 billion dollars and got sentenced 40 months, while Roy Brown stole 100 dollars and got sentenced 15 years. Also, Roy turned himself in because he felt guilty.

3. What would you have done if you were the judge?

- If I were the judge, I would give Paul a 15 year sentence and Roy a couple of months.