##### Laurah Jurca

(Laurel - United States)<p>I currently serve as an ESOL Coach for my school district in Maryland. I work with both ESOL and mainstream teachers to help them improve the quality of their instruction for their English language learners. During my career, I have taught grades k-8, ...

## 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.