## Circumference of a circle - what is the formula for it?

To calculate the circumference of a circle, as with all other geometric figures, we need a formula. What do we know about the wheel itself and what is the pattern? You will find the answer in the article below.

## 1. What is a wheel characterized by?

A circle is a geometric figure that is defined by the center and radius of the circle. The center is a fixed point on a given plane, and the radius is a distance given on the same plane.

A circle is the set of all points in that plane whose center distance is less than or equal to the radius.

Among the figures of a given circumference, it is the circle that covers the largest area. What is the formula for the area of ​​the circle?

A circle is a geometric figure defined by the center of the circle and its radius. How do I calculate the area of ​​a circle? ...

## 2. What is wheel circumference?

The circumference of a circle is the length of its circle, which in turn is its edge. This circle is the set of all points equidistant from the center. It is worth knowing that their distance is equal to the radius, and the center of the circle does not belong to the circle.

As in the case of a circle, we can distinguish three types of segments inside the circle (here only their ends belong to the circle):

• diameter - a segment where both ends are on a circle, and the segment itself passes through its center;
• bowstring - both ends are in the center;
• radius - a line segment with one end centered and the other on a circle.

We can distinguish two types of straight lines:

• secant;
• tangent.

Sieczna has two points in common with the circle, and the tangent has one such point. Mathematical essays-flourishes [4 photos]

Fun and exercises for learning and counting - figures.

see the gallery

## 3. How to calculate the circumference of a circle - formula

The formula for the circumference of a circle is as follows:

O = 2 π r

Where: Here is the circuit; π is a constant number Pi = 3.1415; * r = radius of the circle.

## 4. Problems for calculating the circumference of a circle

Excercise 1.

Calculate the circumference of the circle if r = 5 cm.

• a.10 cm
• b. 33.9 cm
• c. 31.4 cm

Exercise 2.

Calculate the circumference of the circle if r = 13.5 cm.

a. 47.90 cm b. 84.82 cm c. 27 cm