Basic Concepts
In a nutshell: Understand how to compare quantities and solve real-world problems with ratios and rates.
## Making Comparisons
Ratios show the relationship between two quantities. Proportions are equations that state two ratios are equal. Rates compare quantities with different units (like miles per hour).
## Solving Proportions
Use cross-multiplication to solve for missing values in proportions:
\[
\frac{a}{b} = \frac{c}{d} \implies a \times d = b \times c
\]
## Everyday Uses
Ratios and rates are used in recipes, maps, and even sports statistics!
Examples
- A recipe calls for 2 cups of flour for every 3 cups of sugar. What is the ratio of flour to sugar?
- If a car travels 180 miles in 3 hours, what is its average speed in miles per hour?