Proportional Reasoning: Direct Proportion Laboratory
Drag the slider to increase variable x. Notice how variable y scales proportionally to keep the ratio constant!
Input Quantity (x):4
Constant Ratio (k = y/x) = 40
Core Concept: If $x$ and $y$ are in direct proportion, then $\frac{x_1}{y_1} = \frac{x_2}{y_2} = \dots = k$. On the graph, this relationship always charts a perfectly linear path moving out from the origin $(0,0)$.