##### Laura Amatulli

(Rochester Hills - United States)<p>Teaching 8th grade in a middle school in suburban Detroit I have strong interests in Earth Science and leadership. I have been a teacher consultant for our local National Writing Project site, Meadow Brook Writing Project, which keeps me ...

## Lesson 21: Variation

** Description:**The lesson begins with a comparison of data tables and graphs of two functions, one directly proportional (cost of gas) and the other exponential (population), before a definition for direct variation is introduced. Direct variation is then linked to linear function (f(x)= kx)and the scaling property of direct variation is examined (i.e. a multiple of the independent variable will always correspond to that same multiple of the dependent variable). Direct variation with a power of x follows with a test for direct variation before indirect variation and indirect variation with a power of x are introduced.

**Last Updated:**

**Subject(s):**- Mathematics
- Mathematics > Algebra

**Educational Level(s):**- College & Beyond

**Instructional Component Type(s):**- Curriculum: Lesson Plan

- From: San Diego Area Knowledge Exchange for Developmental Math (SAKE)
- Contributed By: SAKE Owner SAKE Owner

The lesson begins with a comparison of data tables and graphs of two functions, one directly proportional (cost of gas) and the other exponential (population), before a definition for direct variation is introduced. Direct variation is then linked to linear function (f(x)= kx)and the scaling property of direct variation is examined (i.e. a multiple of the independent variable will always correspond to that same multiple of the dependent variable). Direct variation with a power of x follows with a test for direct variation before indirect variation and indirect variation with a power of x are introduced.