Direct Variation Explained: Formulas, Tables, and Word Problems

The Organic Chemistry Tutor

This instructional video provides a comprehensive guide to understanding and solving direct variation problems in algebra. It begins by defining direct variation as a linear relationship between two variables, x and y, where y varies directly with x according to the equation y = kx. The video breaks down the concept of the "constant of variation" (k) and demonstrates how to calculate it using the ratio y/x. Through clear, step-by-step examples, the narrator shows how to determine the constant k, write the specific direct variation equation, and then use that equation to solve for unknown values. Key themes explored include the graphical representation of direct variation as a line passing through the origin, the algebraic manipulation of the formula y = kx, and data analysis skills required to identify direct variation from tables of values. The video also transitions from abstract algebraic problems to real-world applications, specifically addressing distance-time word problems. A significant portion is dedicated to verifying proportional relationships by checking if the ratio of y to x remains constant across data sets. For educators, this video serves as an excellent resource for scaffolding algebra lessons. It moves logically from definition to computation, then to data analysis, and finally to application. The clear visual layout helps students follow the procedural steps of identifying k, writing the equation, and substituting values. The inclusion of a word problem with a unit conversion trap (minutes vs. hours) provides a valuable teaching moment about paying attention to details in mathematical modeling.