Lesson OverviewStudents calculate the constant of proportionality for a proportional relationship based on a table of values and use it to write a formula that represents the proportional relationship.Key ConceptsIf two quantities are proportional to one another, the relationship between them can be defined by a formula of the form y = kx, where k is the constant ratio of y-values to corresponding x-values. The same relationship can also be defined by the formula x=(1k)y , where 1k is now the constant ratio of x-values to y-values.Goals and Learning ObjectivesDefine the constant of proportionality.Calculate the constant of proportionality from a table of values.Write a formula using the constant of proportionality.

Students continue to explore the three relationships from the previous lessons: Comparing Dimensions, Driving to the Amusement Park, and Temperatures at the Amusement Park. They graph the three situations and realize that the two proportional relationships form a straight line, but the time and temperature relationship does not.Key ConceptsA table of values that represent equivalent ratios can be graphed in the coordinate plane. The graph represents a proportional relationship in the form of a straight line that passes through the origin (0, 0). The unit rate is the slope of the line.Goals and Learning ObjectivesRepresent relationships shown in a table of values as a graph.Recognize that a proportional relationship is shown on a graph as a straight line that passes through the origin (0, 0).

Doubling something isn't always easy! See if you can figure out why if Tito sells his new pizza for $19.99 he'll be in trouble. Use what you know about area, rates, and proportions to figure out how much Tito should charge or what the dimensions of the new pizza should be in this real world application of math.

Math variety of concepts, this colorful website is sure to give your students the chance show what they know. Concepts covered include rounding, division with decimals, order of operations, ratio, percent, multiplication, and division of fractions, simplifying fractions, and more. Not an interactive site, but great practice activities.

In this lesson, students will learn angle relationships and use these relationships to solve problems.

In this lesson, students will learn how to solve percent of change problems.

In this lesson on similar figures and proportionality, students explore how to identify if figures are similar by applying their knowledge of corresponding angles and sides.

Examine some of the complexities and complications inherent in the development of a micro engine. This video focuses on how MIT researchers have to consider proportions comparing volume and surface area when factoring heat loss, taking math out of the classroom and into real world problem solving.

In this video, learn how mathematics--specifically, proportion, ratio, rate, and conversions--are used in the professional responsibilities of a registered nurse working on the surgical trauma floor. In the accompanying classroom activity, students take on the role of nursing teams, measuring vital signs, analyzing ratios, and calculating metric conversions. [4:35]

Use what you know about percents, ratios, and proportions to figure out the sale price in this real world application of math. See if you can figure out how they calculated the correct price for the shoes Carla likes. Combining percents can be tricky!

In this Cyberchase media gallery, learn about ratio and proportion and how to use an algebraic shortcut to solve proportion problems. In the accompanying classroom activity, students play a game called the "Pom-Pom Nose Push," in which they collect data and determine the ratio of time to distance.

In this video-through footage of the calliope aboard the Belle of Louisville, a church pipe organ, and various instruments at a recording studio-students are introduced to the mathematical concept that the length of a musical pipe or a string has a proportional relationship with the sound it produces. In the accompanying activity, stringed instruments are used to demonstrate the concept presented in the video.

Students build scale models of objects of their choice. In class they measure the original object and pick a scale, deciding either to scale it up or scale it down. Then they create the models at home. Students give two presentations along the way, one after their calculations are done, and another after the models are completed. They learn how engineers use scale models in their designs of structures, products and systems. Two student worksheets as well as rubrics for project and presentation expectations and grading are provided.

This 11-minute video lesson compares population proportions (part 1). [Statistics playlist: Lesson 59 of 85]

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

This 10-minute video lesson compares population proportions (part 2). [Statistics playlist: Lesson 60 of 85]

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

This 16-minute video lesson looks at the hypothesis test for comparing population proportions. [Statistics playlist: Lesson 61 of 85]

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

When you are asked to make an object bigger or smaller, you will ask, "by how much?". In this case, scale factor can help answer the question. In this lesson, we will practice how to enlarge and reduce objects according to the scale factors given to us. A video tutorial is provided.

Graphs of linear relationships are basically just lines and dots. In this video, you will learn the skills to understand and analyze the graphs to get useful information from them. [1:29]

Students "go fishing" and use proportions to learn how estimating is used to determine the size of a population.