# Circumference and circle

The terms of circle and circumference geometry commonly lead to confusion and generate great doubts when it comes to putting them into practice. While some may think they are synonymous, they are not correct. Next, we will explain the **differences between circumference and circle** , and we will also leave you a lot of extra information so that you can get even more into the subject.

Index

## What is a circle

Let’s start by defining what a circle is. According to the **Merriam-Webster** dictionary , it is *“a perfectly round shape: a line that curves so that its ends meet and each point on the line is the same distance from the center* . *” *Next we will leave you an image so that you can know what we are talking about.

## What is a circumference

Now we go on to define what a circumference is. According to the **Merriam-Webster** dictionary , it is *“the length of a line that surrounds something or that forms a circle or other round shape* . *” *Could you tell the circle from the circumference? Do not worry, if you have not achieved it yet, then we will explain it to you quickly and easily.

## Difference between circle and circumference

So what is the difference between circle and circumference? **“Circumference” means the ****length of the line of a “circle** . **” **Easy! To close the idea, let’s look at the image that we will leave below, the circumference is the outer line that is painted blue, while the inner part that is painted pink is the circle, contained within the circumference.

## What is the circumference of a circle

The circumference of a circle is the **distance around the outside of the circle** . It is like the perimeter of other shapes with straight edges, such as squares. You can think of it as the line that defines the shape.

There are two other important distances in a circle, **the radius (r) and the diameter (d)** . Radius, diameter, and circumference are the three aspects that define each circle. Given the radius or diameter and pi, you can calculate the circumference. Diameter is the distance from one side of the circle to the other at its widest points. This will always go through the center of the circle. The radius is half this distance (you can also think of it as the distance between the center of the circle and its edge).

## How to calculate the circumference of a circle

If you know the **diameter or radius** of a circle, you can calculate the **circumference** . To begin, remember that pi is an irrational number written with the symbol π. This is approximately equal to 3.14.

The formula to calculate the circumference of a circle is:

**Circumference of circle = π x Diameter of circle**

This is usually written as **C = πd** . This tells us that the circumference of the circle is three times “and a little” longer than the diameter. We can see this in the graph below:

You can also calculate the circumference of a circle if you know its radius. Remember that the diameter is twice the length of the radius. We already know that C = πd. If r is the radius of the circle, then **d = 2r. **So, **C = 2πr** .

## Circle area

The area of any geometric figure is the **space it occupies in a two-dimensional plane** . Now *what is the area of a circle? *Well, the area of a circle is the space it occupies with a certain radius in a two-dimensional plane. So if your parents want to put a new rug in your circular room, *how much rug do you need to buy? *Again, it will be equal to the area of the room.

**Circle area = πR2**

## Diameter of a circle

The diameter of a circle is the **length of the line that passes through the center and touches two points on its edge** . In the figure below, drag the points and notice that the diameter never changes.

Sometimes the word “diameter” is used to refer to the line itself (which is wrong, since that would be the circumference). In that sense, you can see “draw a diameter of the circle.” In the most recent sense, it is the length of the line, hence it is known as “the diameter of the circle is 3.4 centimeters.”

Diameter is also a chord, a **line connecting any two points on a circle** . It passes through the center point of the circle and is the longest line there can be. The center of a circle is the midpoint of its diameter. That is, it divides it into two equal parts, each of which is a radius of the circle. The radius is half the diameter.

**How to calculate the diameter if you know the radius**

- Given the radius of a circle, the diameter can be calculated using the formula
- Diameter = 2 x R
- where: R is the radius of the circle

**How to calculate the diameter if you know the circumference**

- If you know the circumference of a circle, the diameter can be found using the formula
- Diameter = C / π
- where: C is the circumference of the circle and π is Pi, approximately 3.142

**How to calculate the diameter if you know the area**

- If you know the area of a circle, the diameter can be found using the formula
- Diameter = √ [(4 A) / π]
- where: A is the area of the circle and π is Pi, approximately 3.142