Diameter Definition
It is a specific term of Geometry that represents the distance between two points on the circumference of the circle by passing through the center. Simply, Diameter is the length of the line connecting two points on the circumference of the circle while passing through the center of the circle.
Note:
Learn about Axis in Geometry and Circle here.
Table of Contents
Not all lines passing through two points of the circle are called Diameter. But the line that fulfills the requirements of the above definition will be the diameter of the circle. Other lines are termed Tangent, Radius, and Chords.
Note:
Read about Tangent, Radius, and Chord here in detail.
Formulas to find the Diameter
Like other measurements in Geometry, Diameter can also be found using different formulas. It depends on the measurements we know which formula we are going to use. Let us show you all the general formulas to find this measurement in Mathematics.
When Radius is known
In some problems or questions, you will be given the length of the radius. You can find the diameter of the circle using that length. Here is the general formula that you have to follow in this regard.
D = 2R
In the above formula,
- A “D” stands for Diameter.
- “R” stands for Radius
Let us show you how to solve questions using this formula with the help of an example.
Example 1:
Find the Diameter of the circle with a Radius of 3 meters.
Solution:
As we know the measurement of the Radius, we only have to put this value in the above formula, i.e.
D = 2R
D = 2 (3)
D = 6 meters
When Circumference is known
The circumference is a specific term used in the measurement of the circle. If you are given this value, you can also find the Diameter of that circle using the following formula.
Note:
Read about Circumference in detail.
D = C/π
In the above formula,
- “D” stands for Diameter.
- “C” stands for Circumference.
- “π” is a specific constant that is equal to 3.14.
In the following section, we are going to give you a solution to the problem using this formula.
Example 2:
Find the Diameter of the circle having a Circumference of 4 cm.
Solution:
To solve this question, we only have to put the values on the right side of the above formula.
D = 4/3.14
D = 1.27 cm
When the Area of the circle is known
Another general formula to find the Diameter of the circle involves the Area of a circle. Here is the formula through which you can find the Diameter of the circle using the area.
D = 2 √(A/π)
In the above formula,
- “D”represents the Diameter.
- “A” represents the area.
- “π” is a specific constant that is equal to 3.14.
Example 3:
Find the Diameter of the circle if the Area of the circle is equal to 125 square cm.
Solution:
To find the Diameter, we only have to put the values in the above formula.
D = 2 √(125/3.14)
D = 12.62 cm
Fun Facts about Diameter
- It is the longest chord of a circle.
- The diameter splits the circle into two equal semi-circles.
- The center of the diameter is the center of the circle.
- The diameter connects a maximum of two points from the surface of the circle at a time.
- The twice of radius will give the length of the diameter of any circle.
- A diameter will always be a chord but a chord will not always be the diameter of the circle.
FAQ's
How radius and diameter are related?
Radius is the distance of any point on the circle from the center while Diameter is two times the radius.
Can we find the diameter using circumference?
Yes, we can find the Diameter of the circle using its circumference.
What is half of the diameter called?
Half of the diameter is called the Radius of the circle.
Is it possible to draw a longer chord than the diameter of the circle?
No, the Diameter is the longest chord of any circle.
How many points a diameter can connect from the circumference of the circle?
A diameter can connect only two points on the circumference of the circle at a time.
