Ratio Ratio comparison of two quantities terms a

Ratio • Ratio- comparison of two quantities (terms), a and b, by division where b is not equal to 0. Word form a to b Ratio form a: b Fraction form a/b 55 to 90 55: 90 55/90

Equivalent Ratios • Equivalent ratios have the same value. • To find equivalent ratios, multiply or divide both terms of the ratio by the same non-zero number. • A ratio can be simplified by using the greatest common factor (GCF).

Unit Rate and Unit Cost • Rate- a ratio that compares two unlike quantities. • Examples: finding a better buy, calories per hour, miles per gallon • Unit rate- a ratio that is simplified to have a denominator of 1 unit. It compares an amount, x, to one unit: x/1. • Unit cost- the price per unit of an item.

Which is a better buy? 7 tickets for $42. 67 or 9 tickets for $63. 18 Cost/number of tickets 42. 67/7 or 63. 18/9

Proportions • Proportion- an equation stating that two ratios are equivalent a: b=c: d b and c are called the means a and d are called the extremes Cross Product Rule Product of the means = product of the extremes

Direct Proportion • Direct Proportion- two quantities have a direct proportion relationship when an increase or decrease in one quantity causes the same kind of change in the other. • A sample of paint contains 3 ounces of blue paint and 8 ounces of yellow paint. If you have a 24 -ounce can of blue paint, how much yellow paint should you mix with it in order to make the same color as the sample?

Similar Figures • Similar figures- have the same shape but may be a different size. – Corresponding angles- angles in the same relative position. – Corresponding sides- sides that are in the same relative position.

Inverse Proportions • When an increase or decrease in one quantity causes the opposite kind of change in the other quantity. • You can use like or unlike terms for each ratio.