Line Graphs and Curve Graphs
A line graph joins data points with straight lines to show how a value changes over time. You read up from the x-axis, then across to the y-axis. A curve graph instead uses one smooth curve when the relationship is not linear.
Video Lesson
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Flashcards
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How to Draw a Line Graph?
- Plot each pair of values from a table as a dot on the graph.
- Join neighbouring dots with straight lines.
How to Read a Line Graph?
- Use the x-axis to find the input (the input is often time).
- Read across to the line, then down the y-axis to find the output.
When to Use a Curve Graph?
- Use a curve when the relationship is not linear.
- Fit the data points with one smooth curve.
Line Graphs vs. Curve Graphs
- Line graphs use straight lines to show changes over time.
- Curve graphs use one smooth curve for more complex relationships.
Practice Questions
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At 2 PM, what was the temperature?
Correct! 🎉 +10 pointsNot quite right
The graph shows that at 2 PM, the temperature was C.
According to the graph, during which period did the temperature drop?
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The graph shows a fall in temperature between 2 PM (C) and 3 PM (C).
How many ice creams were sold in total from Monday to Wednesday?
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The ice creams sold were 10 on Monday, 20 on Tuesday, and 15 on Wednesday. Adding them gives .
By how many ice creams did sales increase from Thursday to Friday?
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Sales increased from 25 on Thursday to 50 on Friday. The increase is ice creams.
What was the average number of ice creams sold per day over the weekend?
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The total ice cream sales over the weekend were 50 on Saturday and 30 on Sunday, giving 80. The average is .
A curve graph shows the temperature of a cup of tea over time. The curve decreases steeply at first, then flattens as it approaches room temperature. What does the flattening of the curve represent?
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The flattening of the curve shows that the tea is cooling more slowly as it approaches room temperature.
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Interactive Activity
Explore the difference between linear and curve graphs by interacting with the data points
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Students Also Ask
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A line graph is used to show how a value changes over time. It helps you observe trends, such as temperature through the day or sales across a week. Because the points are joined in order, any rise or fall in the data is easy to follow.
A line graph shows the relationship between two variables. The x-axis usually shows time, such as the hours of a day. The y-axis shows what is being measured, such as temperature. The line joining the points reveals how the measured value rises or falls.
A line graph joins its data points with straight line segments. A curve graph fits all the points with one smooth curve. Both show the relationship between two variables. Line graphs suit trends over time, and curve graphs suit more complex relationships.
Use a curve graph when the relationship between the two variables is more complex than a steady trend. A smooth curve suits values that change gradually. Examples include a plant growing quickly then levelling off, or running speed rising to a peak before falling.
To read a value, find the point on the x-axis, go up to the line, then across to the y-axis. The value where you land is your answer. For example, reading Tuesday on an ice cream sales graph gives 20 ice creams for that day.