## Wednesday, October 12, 2011

### Samantha's Proportion Post

Ratio- shows the comparison of two or more value that has the same units
The image beside shows an example of a ratio, it can be shown three ways:
3/4, 3:4, three compared to four

Rate- a comparison of two quantities in different units
For example 3 apples cost \$1.50, how much would 1 cost?
The answer would be \$0.50, the rate would be 1/\$0.50
Proportion- an equation which states that two ratios are equal
An example would be, Trevor runs 25km in 10 minutes, how long would it take for 100km?
1) 5 hours to travel 360 miles is about 72 mph
hours 5 (÷5) 1
miles 360 (÷5) 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 the orange juice to, to keep the quantities in the same proportion? The orange juice is 50 ml to start with.
apple juice 25ml (x4) 100ml The worker needs to increase 50ml to 200ml.
orange juice 50ml (x4) 200ml

What are the three ways you can prove that equivalent ratio statements are true?
3/4 = 12/16 The first way is horizontal, the next is crisscross and last is vertical.