Graph points to represent mathematical patterns and real-world data.
Imagine you are a treasure hunter with a secret code: for every 2 steps East you take, you must go 3 steps North to find the gold. How could you draw a map that predicts exactly where the next treasure is hidden?
To map a pattern, we use a coordinate plane. This is a flat surface formed by two intersecting lines: the x-axis (horizontal) and the y-axis (vertical). Every location on this map is called an ordered pair, written as . The first number, , tells you how far to move across from the origin . The second number, , tells you how far to move up. Think of it like an elevator: you have to walk across the lobby before you can go up to your floor!
Let's plot the point . 1. Start at the origin . 2. Move units to the right along the -axis. 3. From that spot, move units up. 4. Draw a dot where you landed. You have successfully graphed the relationship where and .
Quick Check
In the ordered pair , which number tells you how far to move vertically (up)?
Answer
The number 2.
Often, math gives us a rule that creates a pattern. For example, 'Multiply the input by 2 to get the output.' We can turn this into a table of values. If our input () is , our output () is . If is , is . These pairs and are coordinates! When we graph multiple points from the same rule, they often form a straight line, showing us a linear relationship.
Rule: 1. Create a table: - If , then . Pair: - If , then . Pair: - If , then . Pair: 2. Plot these three points on your grid. 3. Notice how they form a straight path pointing upward and to the right.
Quick Check
If the rule is 'Add 3 to to get ', what is the ordered pair if ?
Answer
Once your points are on the graph, look at the direction. If the points go up as you move from left to right, the relationship is increasing. This might represent a plant growing over time. If the points go down, the relationship is decreasing, like the amount of water left in a leaking bucket. Graphs allow us to see the 'big picture' of data at a single glance.
A water tank starts with gallons. Every hour, it loses gallons. 1. At hours, . Pair: 2. At hour, . Pair: 3. At hours, . Pair: 4. Graphing these shows a line sloping downward. This visual trend tells us the amount is shrinking over time.
Which axis is the horizontal line on a coordinate plane?
If a pattern follows the rule 'subtract 1 from ', which point belongs on the graph?
On a graph, if the line moves upward from left to right, the y-values are increasing.
Review Tomorrow
In 24 hours, try to explain to someone why the point is different from the point .
Practice Activity
Create a 'Growth Graph' for a fictional pet. If it grows inches every year, plot its height for years and .