Pie Chart Data - Finding The Percent Of A Number

🔑 Key Concepts

• A pie chart shows how a whole group is divided into parts.
• The entire pie chart represents 100% of the data.
• Percentages from different categories can be added when a question asks for “or.”
• To find the number of people in a category, multiply the total by the percent written as a decimal.
• A percent proportion can also be used to find the missing part.

✏️ Worked Examples

Method 1: Use a Proportion

Problem: How many students chose sports or art?

Sports is \(30\%\) and art is \(25\%\).

\(30\%+25\%=55\%\)

\(\frac{55}{100}=\frac{x}{240}\)

\(100x=55\cdot240\)

\(100x=13200\)

\(x=132\)

Answer: \(\boxed{132}\) students chose sports or art.

Method 2: Multiply by a Fraction

Problem: How many students chose sports or art?

The combined percent is \(55\%\).

\(55\%=\frac{55}{100}\)

Multiply the total by the fraction.

\(240\cdot\frac{55}{100}\)

\(\frac{55}{100}=\frac{11}{20}\)

\(240\cdot\frac{11}{20}=12\cdot11=132\)

Answer: \(\boxed{132}\) students chose sports or art.

Method 3: Multiply by a Decimal

Problem: How many students chose sports or art?

The combined percent is \(55\%\).

\(55\%=0.55\)

Multiply the total by the decimal.

\(240\cdot0.55\)

\(240\cdot0.55=132\)

This works because \(0.55\) means \(55\) hundredths of the total.

Answer: \(\boxed{132}\) students chose sports or art.

🧠 Math Vocabulary

• Pie Chart: A circular graph that shows how a whole is divided into parts.
• Percent: A ratio that compares a number to 100.
• Total: The entire amount represented by 100%.
• Category: One section or group shown in a graph.
• Proportion: An equation showing that two ratios are equal.
• Decimal Form: A way to write a percent as a decimal for multiplication.

💡 Main Idea

In this lesson, students use percentages from a pie chart to find the number of people in one or more categories. Since the full pie chart represents 100%, students can add related percentages and multiply the total by the percent written as a fraction, decimal, or proportion.

📚 What You Should Already Know

Students should understand basic percents, fractions, decimals, and how to identify the total amount in a problem. It also helps to know that “or” often means combining categories.

🚀 What Comes Next

After interpreting pie chart percentages, students can solve more complex data problems, compare categories, create circle graphs, and apply percent reasoning to surveys, statistics, and real-world data displays.

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