Scale factors: Ratios and Proportions

Proportions are ratios found using multiplication or division. Middle schoolers solve measurement problems, find a figure's missing dimension, and find the distance between two points. Resource features four lesson plans with detailed...

Sal defines ratios. Then he shows how to write ratios three different ways. This concept is then demonstrated with four examples for finding quantities by using ratios.

Investigate the use of ratios in scale drawings. Learners scale objects up or down using ratios then find the actual size of something using ratios. They apply their knowledge of ratios as they make their own telescopes in science...

Solve a proportion where the variable is the numerator of one of the fractions. How? Just use the multiplication property of equality. This means multiply both sides by the reciprocal value of the denominator. Then the variable will be...

[Free Registration/Login may be required to access all resource tools.] In this lesson students find a scale, ratio, or proportion given actual and scale dimensions. Students examine guided notes, review guided practice, watch...

Middle and high schoolers explore the concept of scale drawings. They discuss what a scale is and that scales provide a ratio. Pupils construct a scale drawing of their classroom using graph paper.

Mastering the art of solving a proportion is not only important for algebra, but it's crucial to geometry and statistics as well. A quick video demonstrates the use of cross multiplication to solve a proportion. The lesson includes...

A model car, a life size car, now compare their sizes. Hmmm. Ok, set up a proportion and then figure out a ratio, and now you can express the relationship in terms of scale. Watch this video and the teacher will demonstrate just how to...

Three angles of one triangle are equal to the corresponding angles in another triangle. Use a ratio of corresponding sides to find the scale factor. Actually, there are two scale factor values. The instructor will explain how to get both...

Scale drawings are an easy and plausible way to represent large things, such as roads and buildings, on paper. This tutorial explains what a scale drawing is and uses the example of a house to demonstrate how a scale drawing works. It...