# Circles

### Popular Tutorials in Circles

#### How Do You Find the Circumference of a Circle if You Know the Diameter?

Trying to find the circumference of a circle? Know the diameter? Then you can use the formula for the circumference of a circle to get the answer! Just plug the value for the diameter into the formula and solve. This tutorial shows you how!

#### How Do You Find the Circumference of a Circle if You Know the Radius?

Trying to find the circumference of a circle? Know the radius? Then you can use the formula for the circumference of a circle to get the answer! Just plug the value for the radius into the formula and solve. This tutorial shows you how!

#### How Do You Find the Radius of a Circle if You Know the Circumference?

Want to find the radius of a circle? Already have the circumference? Then you can use the formula for the circumference of a circle to solve! This tutorial shows you how to use that formula and the given value for the circumference to find the radius. Take a look!

#### How Do You Find the Area of a Circle if You Know the Radius?

If you know the radius of a circle, you can use it to find the area of that circle. Just plug that value into the formula for the area of a circle and solve. Watch this tutorial to see how it's done!

#### How Do You Find the Radius of a Circle if You Know the Area?

Want to find the radius of a circle? Already have the area? Then you can use the formula for the area of a circle to solve! This tutorial shows you how to use that formula and the given value for the area to find the radius. Take a look!

#### How Do You Find the Area of a Circle if You Know the Diameter?

If you have the diameter of a circle, you can use it to find the area of that circle. Just plug that value into the formula for the area of a circle and solve. Watch this tutorial to see how it's done!

#### How Do You Find the Area of a Sector of a Circle?

Trying to find the area of a sector of a circle? Then check out this tutorial! You'll see how to use given information and the formula for the area of a sector to find the answer. Take a look!

#### What is a Circle?

Circles are a fundamental part of math! In this tutorial, you'll be introduced to circles and see the different parts of a circle such as the diameter, radius, and chord. Check out this tutorial to learn about circles!

#### What is Pi?

Some numbers are just so cool that they get their own tutorial. Take the irrational number pi. This number is simply a ratio, but people have been working for years to find more and more digits of pi. Check out this tutorial to learn about pi!

#### What is a Sector and Central Angle?

Just about everything in math has a name! Did you know that a fraction of the area of a circle is known as a sector? This tutorial introduces you to the term sector and gives you examples of sectors. Take a look!

#### What is Circumference?

The circumference of a circle is the distance around that circle. But what is the formula to find the circumference? In this tutorial, you'll learn the formulas for the circumference of a circle. Take a look!

#### What is the Formula for the Area of a Circle?

Did you know that you can figure out the formula for the area of a circle by first turning the circle into a parallelogram? It seems a little weird, but it really works! Watch this tutorial to see how it's done!

#### What is the Formula for the Area of a Sector of a Circle?

A sector is just a fraction of the area of a circle. Did you know that there's a formula to help you find the area of a sector? In this tutorial, you'll learn how to find that formula! Take a look!