Ratio,Rates, Proportions

rate

A comparison of two quantities measured in different units; like miles to gallons

ratio

A comparison of two quantities measured in same units by using division; like girls to boys (both are counting people).

unit rate

A rate in which the second quantity in the comparison is one unit.

unit price

A rate used to find the price of one unit.

Equal sign

A sign making a statement that is stating that both "weights" on each side of the sign are exactly the same. 5+ 8 = 10 + 3 is true because both sides are 13.

proportion

An equation that states that two ratios are equivalent fractions; like 3/9 = 6/18.

x = 9

Solve for x: 3/4 = x/12

x = 18

Solve for x: 3/4 = x/24

x = 45

Solve for x: 5/9 = x/81

Reciprocal

The flip in KCF - where the numerator and the denominator change places. If you multiply a number by this new number, the product is always one.

Scale factor

The number each part in a ratio is being multiplied by to get to the other ratio in a proportion. Only works with multiplication!

True

True or False: 3/4 and 12/16 are proportional.

False! If the boys are listed first - then number relating to the boys is listed first, in this case, the three. So the ratio is 3:5.

True or False: If the ratio of boys to girls is three to five, I can write this as 3:5 or 5:3 - the order of the numbers does not matter.

unit

any measure of one

uni-

one (unicorns, unicycle, universe, etc.)

cross products

one of the methods used to solve a missing number in a proportion - the two products must equal if they are in proportion to each other. Also, a way to test to see if two ratios are in proportion.

8(14) = 5y 112 = 5y 112/5 = y y = 22.4

Evaluate: 5/8 = 14/y

x = 24

Evaluate: 6/7 = x/28

equivalent fraction

Fractions that have the same value

27/48 = 9/16

If there are 27 girls in a class and there are 21 boys, what is the ratio of girls: total?