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Circumference

Master circumference with interactive lessons and practice problems! Designed for students aged 10-16!

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Circumference

Study Guide

Key Definition

The circumference of a circle is the distance around it. It can be calculated using the formula $C = 2\pi r$ or $C = \pi d$, where $r$ is the radius and $d$ is the diameter of the circle.

Important Notes

The value of \pi is approximately 3.14159
The radius of a circle is half of its diameter
Circumference is measured in the same units as the radius or diameter

Mathematical Notation

$\pi$ is the ratio of a circle's circumference to its diameter

$r$ represents the radius of a circle

$d$ represents the diameter of a circle

Remember to use proper notation when solving problems

Why It Works

The formulas for circumference work because they are derived from the definition of \pi, which is the ratio of the circumference of any circle to its diameter.

Remember

Remember the formulas for circumference: $C = 2\pi r$ and $C = \pi d$

Quick Reference

Circumference:$C = 2\pi r$ or $C = \pi d$

Understanding Circumference

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Video explanation of this concept

Beginner

Start here! Easy to understand

Beginner Explanation

The circumference is the distance around a circle. It can be calculated with the formula $C = 2\pi r$ or $C = \pi d$

Practice Problems

Test your understanding with practice problems

Quick Quiz

Single Choice Quiz

Beginner

A bicycle tire has a diameter of 26 inches. What is the circumference of the tire?

Real-World Problem

Question Exercise

Intermediate

Building a Pool

You're building a circular pool with a diameter of 30 feet, and you want to put a decorative border around the outside edge. How much border material do you need?

Recap

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