Comparing and Scaling Quantities

A proportional relationship means two quantities always have the same ratio. If you double one, the other doubles too!

Recognizing Proportions

You can spot proportional relationships in recipes, maps, and speed calculations. They are often written as \(y = kx\), where \(k\) is the constant of proportionality.

Using Proportions

Set up proportions to solve problems like, "If 3 apples cost $6, how much do 5 apples cost?"

Why It Matters

Proportions help you scale up or down in real life, from resizing a photo to converting currencies while traveling.

Quick Check

• If the ratio stays the same, it's proportional.