## Blog Post # How to find the Area and Circumference of a Circle

In Geometry, the circumference of any shape defines the path or the outline that surrounds the shape. In other terms, the circumference is also called the perimeter of the shape, which helps us to identify the length of the boundary of any shape. This article will discuss and study the  Circumference of a circle with its definition, formula, and methods to find the circle’s circumference. Let’s dive into the topic directly.

## What is Circle’s Circumference?

Circumference of the circle or perimeter of the circle is the measurement of the outline of the circle. At the same time, the area of the circle determines the region occupied by the circle. If we open a circle and make a straight line in the circle, its length is the respective circumference. It is ordinarily measured in units, such as cm or the unit m.

When we use the formula to calculate and measure the circle’s circumference, then the same circle’s radius is taken into consideration. Hence, we need to know the exact value of the radius as well as the diameter to estimate the perimeter of the circle.

### Circumference of a Circle Formula:

The Circumference or also known as the perimeter of a circle = 2πR

where,

R is the radius of the given circle

π is the mathematical constant with a standard estimated value of 3.14

## Area of a Circle Formula

The area of a circle is the region encircled by the circle itself or the entire space covered by the circle. The standard formula to find the area of the circle is;

A = πr2

Where r is the radius of the circle, this formula fits all the circles with different radii.

## Perimeter of Semi-Circle

To find the perimeter of the semi-circle, we divide the circle into two equal parts. Consequently, the perimeter of the semi-circle also becomes half.

Hence, the standard formula of the Perimeter = πr +2r.

## Area of Semi-Circle

The area of the semicircle is the area that a semi-circle has occupied in a given 2D plane. The area of the semi-circle is equivalent to half of the area of a circle, whose radii are equal or the same.

Therefore, the formula to find the area of a semi-circle = πr2/2

## The Radius of a Circle

The distance calculated from the center to the outer line of the circle is called a radius. It is the most important quality of the circle because most of the formulas are based on the area, and the circumference of the circle is derived from the radius of the circle. When you double the radius of a circle, it is called the diameter of the circle. The diameter cuts the circle into two identical and even parts, which is called a semi-circle.

## Who calculated the circumference of the earth first?

The first person to ever calculate the Earth’s circumference was Eratosthenes, a Great Greek mathematician, in 240 B.C. He discovered that objects in a city on the Northern Tropic do not throw a shadow at noon on the summer solstice, but they do in a more northerly upward location. After knowing this, and the distance between the locations, he finally succeeded in calculating the Earth’s circumference.

## What is the circumference of a circle with a radius given 1 meter?

To calculate the circumference of a circle with a radius of 1 meter, one should simply follow these easy steps given below:

1. First, multiply the radius by 2 to get the diameter of 2 meters.
2. Then, multiply the result by π, or 3.14, a standard estimation used for pie.

And then, we get the circumference of a circle with a radius of 1 meter that is 6.28 meters.

Cuemath is an online learning platform that helps students explore a circle’s circumference in detail using various learning tools, making learning super fun and easy.