# Percentages, Ratios and Proportions

Percentage

A percentage is a part per 100. The symbol is %.

A percentage will always be....

Out of 100

100% is the same as saying.....

100/100. For example: 100/100 of this circle is shaded so 100% of this circle is shaded.

100% of any number is...

Just the number unchanged. For example: 100% of 75 is 75

0.5 and 1/2 are the same as

50%

0.25 and 1/4 are the same as

25%

0.75 and 3/4 are the same as

75%

10% converts into

10/100...or...1/10...or...0.1

20% converts into

20/100...or...2/10...or...0.2

25% converts into

25/100...or...1/4...or...0.25

30% converts into

30/100...or...3/10...or....0.30

50% converts into

50/100...or...5/10...or...1/2...or...0.5

75% converts into

75/100...or...3/4...or...0.75

1% converts into

1/100...or...0.01

5% converts into

5/100...or...0.05

90% converts into

90/100...or...9/10...or...0.9

100% converts into

100/100...or...1 whole...or...1.0

What is a ratio?

A comparison of values; a representation of the relationship between values.

What are three ways to show ratio values?

As fractions, with a colon ( : ) in between, or with the word "to" in between, i.e. 1/4 , 1:4, 1 to 4

What is a proportion?

Two equal ratios/equivalent fractions.

How do you solve a proportion?

Multiply diagonally, divide by what's left.

How do you simplify proportion answers?

Reduce, but do not rename if improper.

Equivalent Fractions

Fractions that have the same value, but different numerators and denominators.

proportional relationship

A relationship between two values in which the ratio of one value to the other quantity is constant.

What are the three things to keep in mind when creating a ratio?

1) Include the information the problem asks for; 2) Put in the information in the order the problem requests; 3) Reduce your answer, but do not rename it if improper.