# Pre Alg. Chapter 6

## 20 terms

### certain event

an event that is sure to occur and has a probability of 1.

### commission

pay that is equal to a percent of sales.

### complement

the opposite of an event.

### cross products

the product of the numerator of one fraction and the denominator of another.

### discount

the amount by which a price is decreased.

### event

any outcome or group of outcomes.

### impossible event

an event that will never occur and have the probability of 0.

### indirect measurement

uses proportions in similar triangles to measure the distances that would be difficult to measure directly. (5ft. tall person standing near a tree has a shadow of 4 ft. long, the tree has a shadow 10 ft. long, you use this to find the height of the tree which is 12.5 ft.)

### markup

the amount of increase in price.

### odds

a ratio that compares the # of ways an event can occur (successes) to the # of ways it cannot occur (failures)

### outcomes

possible results of an action.

### percent

a ratio that compares a number to 100.

### percent of change

the percent something increases or decreases from its original amount.

### probability

a measure of how likely it is that some event will occur

### proportion

an equality of two ratios.

### rate

a ratio that compares quantities measured in different units.

### ratio

a comparison of two quantities by division.

### scale drawing

a drawing of an object that is different in size (usually smaller than the original) but keeps the same proportions

### similar figures

has corresponding angles that are congruent and corresponding sides that are in proportion

### unit rate

a rate that has a denominator of 1