--- title: "Pie charts and line graphs" description: "Interpret and construct pie charts and line graphs; use these to solve problems" canonical: https://lightmysky.com/learn/mathematics/pie-charts-and-line-graphs-mt_bESTSBB0wK source: https://lightmysky.com/learn/mathematics/pie-charts-and-line-graphs-mt_bESTSBB0wK.md retrieved: 2026-09-12 --- > **Agent view.** This is the Markdown twin of the page, for tools and assistants. > When to use this site, and the call that answers each job: https://lightmysky.com/agent-instructions.md > API description (OpenAPI 3.1): https://lightmysky.com/openapi.json · Authentication: https://lightmysky.com/auth.md > Pricing: https://lightmysky.com/pricing.md · Catalog: https://lightmysky.com/llms.txt · Full catalog: https://lightmysky.com/llms-full.txt > Every machine-readable file on this domain: https://lightmysky.com/.well-known/ai-catalog.json > Ask for Markdown with `Accept: text/markdown`, a `.md` address, or `?mode=agent`. # Pie charts and line graphs Interpret and construct pie charts and line graphs; use these to solve problems Subject: Mathematics · Area: Data & Statistics · Ages 10 to 11 Page: https://lightmysky.com/learn/mathematics/pie-charts-and-line-graphs-mt_bESTSBB0wK ## Ready when they can - Read values from a line graph showing temperature over a day and identify trends - Construct a pie chart from given data by calculating sector angles - Use a pie chart to determine the actual quantity represented by each sector given the total ## Lesson: Reading pie charts and line graphs A line graph shows how something changes over time. Each dot is a value at a certain time, and the dots connect with a line. When the line goes up, the value is increasing. When it goes down, the value is decreasing. When the line is flat, the value is staying the same. **Example.** A line graph tracks temperature through a day: 10°C at 6am, 14°C at 9am, 20°C at 12pm, 22°C at 3pm, then 18°C at 6pm. The line rises all morning, keeps climbing into early afternoon, then turns and falls toward evening. The warmest point on the graph is 3pm, right where the line changes direction. *(drawing: Each bar is one temperature reading: 10°C at 6am climbing to 22°C at 3pm, then dipping to 18°C at 6pm. A line graph draws these same values as dots joined by a line.)* A pie chart shows how a whole amount splits into parts. The whole circle stands for the total, and each slice, called a sector, stands for one part. You already know a full turn is 360°, and that's exactly how much a full circle holds. To find a sector's angle, work out what fraction of the total that part is, then multiply by 360°. **Example.** 24 children picked a favourite fruit: 12 chose apples, 6 chose bananas, and 6 chose grapes. Apples are 12 out of 24, which is half, so that sector gets half of 360°, which is 180°. Bananas and grapes are each a quarter, so each of those sectors gets 90°. **Tip.** Once you know a sector's percentage or fraction, you can find the real quantity, too. Just multiply the total by that fraction. If a $40 budget pie chart shows 25% spent on Fun, that's 25% of $40, which is $10. **Recap.** A line graph shows change over time; a pie chart shows a whole split into parts, each sector sized by its fraction of 360°. ## Practice 17 questions on this page, each with its working shown. ## Needs first - [Measuring angles](https://lightmysky.com/learn/mathematics/measuring-angles-mt_4MFUAsbx_6) - [Reading and comparing bar and line graphs](https://lightmysky.com/learn/mathematics/reading-and-comparing-bar-and-line-graphs-mt_H6LlpWgEYS) - [Angle Sum Rules](https://lightmysky.com/learn/mathematics/angle-sum-rules-mt_oqziWKry-L) - [Calculating Percentages](https://lightmysky.com/learn/mathematics/calculating-percentages-mt_PNSyfH56eQ) - [Data collection and display vocabulary](https://lightmysky.com/learn/mathematics/data-collection-and-display-vocabulary-mt_u5HkSxZECM) ## Opens up - [Moving between representations of a relationship](https://lightmysky.com/learn/mathematics/moving-between-representations-of-a-relationship-mt_9KmVWCuh5_) - [Frequency tables, bar charts and pie charts](https://lightmysky.com/learn/mathematics/frequency-tables-bar-charts-and-pie-charts-mt_eKJG-0eC6D)