December 19, 2012

Please get out a pencil and your notes journal, and clear your

desk. Please be ready as soon as the bell rings!!!!

Ratio Quiz Bonus Question

• There are 36 students on the soccer team. The ratio of boys to girls is 2:7. How many boys are on the team?

Unit Rate

• Unit rate is a ratio comparing something to one of another.– Examples:

• miles per hour• Miles per gallon• Dollars per hour• Words per minute

• You find the unit rate by setting up a ratio and dividing by the bottom number in the ratio.

Proportion

• A proportion is two equivalent ratios.– Example: 2 girls to 3 boys = 6 girls to 9 boys– Example: 9 blue to 7 red =90 blue to 70 red

You solve a proportion by figuring out what was done to the top or bottom and find the equivalent ratio(fraction)

Percents

• A percent means out of 100. (Just a fraction over 100)

• To determine the fraction, you put the percent over 100, then reduce to simplest form.

• To convert to a percent from a fraction you form a proportion with the fraction equal to x over 100.

• Ex: 23% = 23/100• Ex: 2/5 = x/100

Changing from a decimal to a percent

1. Read the decimal. Ex: 0.57 is read as fifty seven hundredths.

2. Write the decimal as a fraction. Ex: fifty seven hundredths is written as

3. Set up the proportion from the fraction to percent. Ex:

4. Solve the proportion. Ex:

Changing from a percent to a decimal

1. Write the percent as a fraction over 100. Ex: 20% =

2. Read the fraction. is read as twenty hundredths.

3. Write the decimal that is the same as what you read. Ex: twenty hundredths is written as 0.20.