__________________________________________________________________________________________________________
Circle - Circumference, Radius and Diameter
Circle:
What is circle? Circle is a simple shape of geometry where a set of points in a plane are equidistant from a given point. In the image below, point O is the center if the cricle and all the points on the circumference are equal distance from it. A cricle can be also defined as closed curve which divides a plane. The word circle derives from a latin word called kiroks from the base ker which mean bend or curve. The shape circle has been known before history is recorded. Circles exists everywhere such as Sun and Moon. Circle is core for some of the great inventions such as wheels and astronomy. Below are some key facts about circles
> Euclid's Elements in 300 BC defined elements of circle.
> Rhind Papyrus in 1700 BC devised a method to find area of a circle.
> Lindermann in 1880 provided transcendence proof of pi (π).
Circle has various parts such as Area, Circumference, Diameter, and Radius. Greek letter pi (π) plays an important role when it comes to calculating various parts of circle. π ≈ 3.14159. Use the calculators above to calculate different parts of circle.
What is Radius?
Radius is an important aspect of circle. Radius is the line segment between the center and circumference of a circle. In another word, radius is the distance between the centers of the circle to any point of the circle. Radius is half of a diameter. Radius is denoted with letter r.
Calculate the Radius of a circle:
Radius can be calculated from various parts of circle such as diameter of a circle, circumferences of a circle or even area of a circle. Use the Radius calculator to double check your homework. Formulas to calculate radius are below.
Option A:
If diameter is given, calculate the radius?
d = 2r so r = d/2
Radius is half of diameter.
Option B:
If circumference is given, calculate the radius?
C = 2 πr
r = c/2
Option C:
If area is given, calcualte the radius?
A = πr2
r = sqrt(A/ π)
What is Diameter of a circle?
What is diameter? Diameter of a circle is the distance through the center of the circle. Diameter of a circle stays the same in any direction. Two radiuses make one diameter and it is denoted with letter D.
Calculating Diameter:
Diameter can be calculated from various parts of a circle. Use the diameter calculator above to calculate. Formulas for calculating diameters are below.
Option A:
If Radius is given, what is diameter?
D = 2 * r
Option B:
If Circumference is given, what is Diameter?
C = 2 πr or C = D * π
D = C/ π
Option C:
If area is given, what is Diameter?
A = πr2 or r = sqrt(A/ π)
D = 2 * r
D = 2 * (sqrt(A/ π))
What is circumference of a circle?
What is circumference of a circle? The distance around the circle is called the circumference of a circle. It is the parameter of a circle. Circumference is mostly denoted by letter C.
Calculating Circumference
Circumference can be calculated from various parts of circle. Use the circumference calculator above to calculate. Formulas to calculate circumference are below.
Option A:
If Radius is given, what is the circumference of a circle?
C = 2 πr
Option B:
If Diameter is given, what is the circumference of a circle?
C = 2 πr or C = πd
Option C:
If area is given, what is the Circumference of a circle?
A = πr2 or r = sqrt(A/ π)
Since C = 2 πr we substitute r with sqrt( A/π)
C = 2 π * sqrt( A/π)
What is Area of a circle?
Area of a circle tends to be one of the crucial calculations in geometry/math. The Area calculator above provides you with the flexibility to calculate area based on different inputs.
Calculating Area
Formulas to Calculate are below.
Option A:
If radius is given, what is area of a circle?
A = πr2
Option B:
If diameter is given, what is area of a circle?
A = π(D/2)2
Option C:
If circumference is given, what is area of a circle?
A = π(C/2 π) 2
Suggested Calculators:
Triangle Calculator – Calculate different aspects of triangle
Rectangle Calculator – Calculate different aspects of rectangle
Square Calculator – Calculate different aspects of Square
Back to Top
__________________________________________________________________________________________________________