Circle Graphs
A circle graph (also called a pie chart) shows how a whole is divided into parts, with each wedge representing a portion of the total. In Grade 4 math from Saxon Math Intermediate 4 Chapter 6, students interpret circle graphs—for example, a graph showing how a 24-hour day is divided among sleeping, school, and free time. Each slice's size reflects its fraction of the total, making circle graphs ideal for showing relative proportions at a glance.
Key Concepts
Property A circle graph shows how a whole is divided into parts. A circle graph is sometimes called a pie graph, where the 'pie' is cut into 'slices' that show the size of the parts.
Example In a 24 hour day, if sleeping takes up 9 hours, the 'Sleeping' slice covers $\frac{9}{24}$ or $\frac{3}{8}$ of the entire circle. If school is 7 hours and homework is 2 hours, together they make up a single slice representing $7+2=9$ hours of the day. A budget shows 50% for rent, 30% for food, and 20% for fun. The 'Rent' slice would be half the entire circle.
Explanation This is a 'pie' chart that shows how a whole is sliced up. Each piece represents a part of the total, like how you spend your 24 hour day or a monthly budget.
Common Questions
What is a circle graph?
A circle graph (pie chart) represents a whole divided into parts. Each slice shows how large that part is relative to the whole. All slices together equal 100% or the total.
How do you read a circle graph?
Each slice is labeled with a category and often a percent or fraction. The larger the slice, the bigger that portion of the whole. Compare slice sizes to see which category is largest or smallest.
When do Grade 4 students learn about circle graphs?
Circle graphs are introduced in Chapter 6 of Saxon Math Intermediate 4 as part of data analysis and graphing.
How does a circle graph differ from a bar graph?
A bar graph compares exact amounts between categories; a circle graph shows how parts relate to the whole. Circle graphs are better for showing proportions and percents.
What fraction of the circle does a category represent if it covers 90 degrees?
90° is 90/360 = 1/4 of the full circle, so that category represents 1/4 of the total, or 25%.
What are real-world examples of circle graphs?
Budget breakdowns (rent, food, savings), time-use surveys, and survey results on favorite activities are all commonly displayed with circle graphs.