Percent of Change

• A special ratio is PERCENT.

• The word PERCENT means:

“out of”

00

1

35% =

99% =

12.5% =

35100

99100

12.5100

So you can turn any percent into a ratio:

What if we DON’T KNOW a percent yet… how would we write the ratio??

100??? % =

لجبرا USE ALGEBRA !

X

EXAMPLE: 32 is what percent of 56??

Set up your ratios…32

56= _x_

100 …and solve it !!!

Sorry, Mr. AYou have to write

it yourself!!

Percent CHANGE

Sometimes we are asked to see how much something changes.

To find the Percent Change, follow these steps!

Original Price : $18

New Price : $10

What is the Percent Changein the price?

Increase or Decrease ??DECREASE

By how much?$18 – $10 = $8

Make a ratio comparingthe changechange over the originaloriginal

$8$18

$8$18

Set the change ratioequal to the percent ratio

= X100

SOLVE IT !!!!

To find the percent of something, just set up a proportion!

EXAMPLE: Sales Tax in Florida is 7%. How much tax will you pay for a $12,000 car?

7100=

X

12,000

• Remember a TAX is something you add to the original price.

• A DISCOUNT is something you subtract from the original price.