Line Graphs
Learn
What is a Line Graph?
A line graph is a type of chart that uses points connected by lines to show how data changes over time. It's perfect for showing trends, patterns, and changes in data.
Line graphs help us answer questions like: "Is something increasing or decreasing?" and "How quickly is it changing?"
Parts of a Line Graph
Title
Tells you what the graph is about. Always read the title first!
X-Axis (Horizontal)
Usually shows time periods like days, weeks, months, or years.
Y-Axis (Vertical)
Shows the quantity being measured, like temperature, sales, or height.
Data Points
Dots that represent each piece of data. They show the exact value at each time.
Line Segments
Lines connecting the dots show how data changes between points.
Scale
Numbers on the axes that help you read exact values from the graph.
Temperature Over a Week
Reading a Line Graph
Read the Title
Understand what the graph is measuring and what time period it covers.
Check the Axes
Look at what each axis represents and the scale (intervals between numbers).
Find Specific Values
To find a value, locate the point on the x-axis, then read across to the y-axis.
Identify Trends
Look at the overall direction: Is the line going up, down, or staying steady?
Types of Trends
Increasing Trend
Line goes up from left to right. Values are getting larger.
Decreasing Trend
Line goes down from left to right. Values are getting smaller.
Steady/Constant
Line stays mostly flat. Values stay about the same.
Examples
Example: Reading Temperature Data
Using the temperature graph above:
- What was the temperature on Tuesday? Find Tuesday on the x-axis, go up to the point, then read across to the y-axis: 68°F
- Which day was hottest? Find the highest point on the graph: Thursday at 75°F
- What's the trend from Monday to Thursday? The line goes up - temperature is increasing
Example: Finding the Change
If the temperature was 65°F on Monday and 75°F on Thursday:
Change = 75 - 65 = 10°F increase
The temperature increased by 10 degrees over those 4 days.
Interactive Line Graph Builder
Create Your Own Line Graph
Enter data values for each day and click "Draw Graph" to see your line graph!
| Day | Value |
|---|---|
| Mon | |
| Tue | |
| Wed | |
| Thu | |
| Fri |
Practice Problems
Books Read Each Month
Problem 1
Based on the graph above, how many books were read in March?
Problem 2
Which month had the most books read?
Problem 3
What is the overall trend from January to April?
Problem 4
How many more books were read in April than in January?
Problem 5
Between which two consecutive months was the biggest increase?
Check Your Understanding
Question 1
What makes a line graph different from a bar graph?
Question 2
If a line on a graph is very steep going upward, what does that tell you?
Question 3
When would you choose a line graph instead of a bar graph?
Summary
Shows Change
Line graphs display how data changes over time.
Key Parts
Title, x-axis, y-axis, data points, and line segments.
Trends
Identify increasing, decreasing, or steady patterns.
Read Values
Use the axes to find exact data values at any point.
Next Steps
- Practice reading line graphs in newspapers or online
- Try creating your own line graph with real data (like daily temperatures)
- Move on to Numerical Patterns to learn more about finding patterns in data