Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Definition: A line graph is used to show how data changes over a continuous period of time.
The X-axis (Horizontal): Usually represents the independent variable, most commonly time (seconds, days, months, years).
The Y-axis (Vertical): Represents the dependent variable or the quantity being measured (temperature, height, distance).
Plotting Points: Data is marked as coordinates (dots) where the x-value and y-value meet.
Connecting Dots: Points are joined by straight lines to visualize the trend or pattern.
Interpreting Trends: An upward line indicates an increase, a downward line indicates a decrease, and a flat line indicates no change.
Scale Selection: Choosing a scale that fits all data points clearly on the grid using equal intervals.
📐Formulae
💡Examples
Problem 1:
A line graph shows a plant's height was 4 cm on Monday and 10 cm on Friday. What was the growth over these 5 days?
Solution:
Explanation:
To find the change or growth, subtract the starting value (Monday) from the ending value (Friday). The plant grew 6 cm.
Problem 2:
You are plotting temperature data where the highest temperature is 35°C. If your Y-axis has 7 major grid squares, what should each interval represent?
Solution:
Explanation:
Divide the maximum value by the number of squares available to find a suitable scale. Each grid line should represent 5°C.
Problem 3:
In a graph representing a car's journey, the line is perfectly horizontal between 2:00 PM and 2:30 PM. What does this tell you about the car's movement?
Solution:
The car was stationary (stopped).
Explanation:
A horizontal line on a distance-time graph indicates that the distance is not changing as time passes, meaning the object is at rest.