Ratio: Writing Equations
Write an equation in the form representing a proportional relationship, replacing and with single-letter quantity variables.
Frequently Asked Questions
How do I convert between percentages, decimals, and fractions?
Use our interactive conversion tool to practice and learn the relationships between formats. Tip: Click 'Show Examples' for a clear guide on how to solve each type!
Do I need to simplify fractions?
Yes, you must simplify your fractions! Our tool requires the most simplified form for your answer to be accepted. Unsimplified fractions will be marked as incorrect.
How do I know if a table or graph represents a proportional relationship?
In a table, the ratio yx must be constant for all rows ($y = kx$). On a graph, it must be a straight line passing through the origin (0,0).
How do I write an equation for a proportional relationship?
Find the constant of proportionality $k = \frac{y}{x}$ (unit rate), then write the equation $y = kx$. Replace $y$ and $x$ with the single-letter quantity variables given in the problem (for example, $d = 50t$ for distance $d$ and time $t$).