Grade 7 · Data · Sampling, Percentages, and Circle Graphs

Build a Trustworthy Circle Graph

A polished graph cannot repair biased data. Trustworthy conclusions begin with a suitable question, representative collection method, and correctly scaled display.

The big idea

Every sector is a percentage of 360 degrees

A category containing 25% of the data needs 25% of a full turn: 0.25 × 360° = 90°.

Work it through

Create a sector for 35% of a sample

1. Convert 35% to 0.35.
2. Multiply 0.35 × 360° = 126°.
3. Label the category and percentage clearly.
4. Confirm that all categories total 100% and all angles total 360°.

For parents and educators

Ontario curriculum alignment

Grade 7 Mathematics · Strand D: Data

View supported expectations

D1.1 · Data Collection and Organization

Explain why percentages are used to represent the distribution of a variable for a population or sample in large sets of data.
D1.2 · Data Collection and Organization

Collect qualitative data and discrete and continuous quantitative data to answer questions of interest, and organize the sets of data, including using percentages.
D1.3 · Data Visualization

Select from various graphs, including circle graphs, the graph best suited to represent data; display the data with proper sources, titles, labels, and scales; and justify the choice.
D1.4 · Data Visualization

Create an infographic about a data set, representing the data in appropriate ways, including in tables and circle graphs, and incorporating information that helps tell a story.