Lesson 9: Represent Problems on the Coordinate Grid

Property

An ordered pair $(x, y)$ plotted on a coordinate grid represents a specific relationship between two quantities in a real-world problem. The $x$-coordinate represents the value of the first quantity, and the $y$-coordinate represents the corresponding value of the second quantity.

Examples

• If the point $(3, 9)$ represents the cost of movie tickets, it could mean that $3$ tickets cost a total of $9$ dollars.
• If the $x$-axis represents the number of weeks and the $y$-axis represents total savings, the point $(4, 20)$ means that after $4$ weeks, the total savings is $20$ dollars.
• If a graph shows the relationship between hours worked ($x$) and pages read ($y$), the point $(2, 50)$ indicates that in $2$ hours, $50$ pages were read.

Explanation

Once you plot ordered pairs on a coordinate grid, each point tells a story about the problem. The $x$-value and $y$-value are not just numbers; they are corresponding values from two related patterns or scenarios. By reading the labels on the axes, you can understand what each point represents in the context of the problem. This skill allows you to translate the visual information from the graph back into a meaningful statement.