This lesson will teach you all about Ratios and Proportions. Beginning with definitions and illustrative examples, you will move quickly into cross products and cross multiplication before seeing rates in mathematics and their counterparts in real life. Four video examples at the end make sure you know how to use your new found knowledge.
A ratio is a
comparison of two quantities by division.
A proportion is an
equation stating that two ratios are equal.
Two ratios are
equal if and only if their cross products are equal. To solve a
proportion, use the fact that the cross products are equal. Set
the cross products equal to each other and solve for the unknown
A rate is a ratio
of two quantities having different units of measurement.
involving rates by using proportions.
A scale is a ratio
that compares the size of a model to the size of the actual object.
Proportions can be used to solve problems involving scales.
Ratios and Proportion
Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.