In geometry, a circle is a two-dimensional structure in which all of the points on its own surface are equidistant from the central axis. The radius of a surface is the distance between its core and any point on it.

The diameter of a circle is defined as the distance from across the core in between the spot on the circle’s surface as well as another position on the circle’s surface. The radius is times as effective as the diameter, to put it another way. The circle’s diameter is identical to the circle’s longest chord. The notations for diameter are ‘d’, “, ‘D’, and ‘Dia.’

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**What is Circumference?**

The perimeter of an enclosed figure is determined by the length of the demarcation line. It’s known as the circumference of the circle. The perimeter of an object’s interior diameter is its circumference. When a circle is extended to produce a linear teck model, the perimeter is the distance along which the line of symmetry is acquired. You must understand the implications of ‘pi’ in order to compute the radius of a sphere.

The diameter of the circle is equal to the length of the circle’s edge. When a rope is properly looped around this boundary, its circumference matches its length, which can be calculated using the formula: 2r units = circumference/perimeter, where r is the circle’s radius, popularly known as ‘pi.’ The ratio is the same for all circles. Consider a circle’s radius ‘r’ and circumference ‘C’. In order to complete the circle.

**Diameter of a Circle – Formula**

The following are the several methods for calculating a circle’s diameter:

The diameter of a circle can be computed if the radius is known:

**R= 2D, **Where “R” denotes the circle’s radius.

If you know the circumference of a circle, you can use this formula to figure out how big it is D = C/π**, **where, The circumference of a circle denoted by C is a constant value, roughly equivalent to 3.14.

If you know a circle’s area, you may use this formula to figure out how big it is.

D=√4A/π

(or)

D=2√A/π

Where, A is the area of a circle.

**Dimensional Characteristics**

The qualities of a circle’s diameter are as follows:

- The diameter of a circle is the length of its longest chord.
- The diameter divides the circle into two equal pieces, yielding two semicircles of equal size.
- The circle’s center is the diameter’s halfway.
- Half of the diameter should be used for the radius.

## Examples: To find the diameter of a circle, solve the problems below.

**1st example**:

If the radius of a circle is 3 cm, calculate its diameter.

Solution:

Given:

R=3 cm Radius

We know that if the radius is known, the diameter can be calculated using the formula:

2R = D

When R = 3 cm is substituted in the formula, we get

D equals 2(3)

D is around 6 cm.

**2nd Example**:

A circle has a circumference of 36 cm. Determine the circumference of a circle.

Solution:

Given:

C = 36 cm circumference.

We are well aware of this.

D is equal to C/

Now, in the formula, substitute C = 36 cm and = 3.14.

D = 36/3.14 D = 36/3.14 D = 36/3.14 D

11.5 D (approximately)

As a result, a circle’s diameter is approximately 11.5 cm.

**3****rd**** Example:**

Given a 125 cm2 area, calculate the diameter of a circle.

Solution:

Given:

A = 125 cm2 is the area of a circle.

If the circle’s area is known, the diameter of a circle may be calculated using the following formula:

D=2√Aπ

Substituting the values of A and in the formula yields

D=2√1253.14

D=21253.14

D= 2(6.31)

D (12.62) (approximately)

As a result, a circle’s diameter is 12.62 cm.