Direct Variation Made Simple (With Real-Life Examples)
Direct variation doesn’t have to be confusing! In this lesson, we’ll break it down step by step so you’ll know how to go from an equation, table, graph, or even a word problem and connect them all. Direct variation is written as y = kx where k is the constant of variation.
We’ll practice with real examples like the cost of jeans, driving distance formulas, servings of rice, and more. By the end, you’ll be able to spot direct variation in any form and explain why the graph always goes through the origin.
Direct variation equations have the form 𝑦=𝑘𝑥, where k is called the constant of variation.
The graph of 𝑦=𝑘𝑥 always passes through the origin (0,0)
k can be an integer, fraction, or decimal.
Direct Variations commonly use the phrase “varies directly”
To calculate k: 𝑘=𝑦/𝑥. Where y is the dependent variable and x is the independent.
Direct Variations are similar to Proportional Relationships: 𝑦=𝑚𝑥, where m is the slope or rate.
This video could work for #Algebra students who were absent, or in a flipped classroom.
See my full list of Algebra 1 lessons: • Algebra 1 Lessons
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0:00 Intro
1:03 Vocab
2:37 Table to Graph
4:36 Words to Graph
6:34 Equation to Graph
9:25 Table to Equation
11:56 Graph to Equation
14:51 Words to Equation
16:26 How to find k
17:29 Example- write equation given x and y
19:51 Example 2- write equation given x and y
21:39 Example- write equation -perimeter
23:06 Wrap-Up
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