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RATIOS, PROPORTIONS, RATES

A ratio is a comparison of two quantities. Ratios can be written several ways. A ratio of 7 to 6 may be written 7:6 or could be written 7/6. The word ratio is pronounced “rash – e – o” with a “long a” in “rash”, “long e”, and “long o”.

A very useful problem solving technique is writing a proportion for numerical information that can be written in ratio form. Once a proportion is written, cross multiplication is used to write an equation and solve the problem.

Some measurements are a combination of two units such as miles per hour or meters per second called “derived measurements”. We will solve some word problems that use derived measurements.

SCALE FACTORS AND MODELS

A scale factor is a factor that can be used to multiply the measurements of an object for the purpose of finding the measurements of a second object that is in proportion to the original object.

Scale models are used in many industries. In constructing buildings and making new vehicles, scale models are used as a guide for measuring building materials needed and assembling the parts.

Ratios