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Use this online calculator to calculate the properties of a circle. The circle calculator will automatically calculate all mathematical variants of a circle simply by entering one of the circle elements. Simply enter the radius or circumference or diameter to calculate the area and spherical area of a circle. Each circle factor will calculate its corresponding mathematical relation.

Why a circle calculator? Well, let's begin with the circle itself. Of all the geometrical shapes that we come across in our daily life, circle is possibly the most interesting shape. Be it the sun, the moon, or bike/car tires, everything is a circle. When man first invented the wheel, it had to be a circle because, well, nothing else will rotate as effortlessly as a circle. Funnily enough, when things get back to where they were, we find ourselves saying, "Life has come to a full circle."

Oh, and yes, remember when you fell in love with someone's blue, green or hazel eyes? That's the color of the pupil, and it's a circle too! And who can forget the age-old question, "Why does a round pizza come in a square box?" Pizza is love, and it is a circle too!

Now that we realize how often we get to see a circle, let's see what defines a circle in the world of calculations.

In simple and easy terms, a circle is a simple geometrical 2D shape in which all the points on the boundary (circumference) are equidistant from a given centre point. Mathematicians also define a circle as a square with infinitely long sides.

While the second definition is equally correct, it often leads to confusion among young students. Thus, basic mathematics textbooks stick to the first definition alone.

You must agree, for most of us the most peculiar thing about drawing a perfect circle is that it's so effortful to draw it with a running hand. We always needed a compass as a kid, and still do, to create the perfect one.

A circle is an interesting shape from a layman as well as core geometric perspective. Here are some of the most interesting properties of a circle:

- All circles are similar.
- Circles with equal radii are congruent circles.
- Circles within a circle with decreasing radii but a common center are called concentric circles.
- From any point of contact, a tangent is always perpendicular to the radius.
- A radius drawn perpendicular to the chord will always bisect the chord (divide the chord into two equal parts).
- Diameter is twice the length of the radius.
- Diameter is also the longest chord of a circle.

It is easy to remember the formulas for calculating the area of a circle (πr2) or its circumference (2πr or πD where D is 2r, twice the length of the radius). But doing the real math manually when you know π itself is a fraction (22/7 or 3.14) is a different story altogether.

This is where a circle calculator comes into the picture. If we told you that a certain circle has radius "x" and you were asked to calculate its circumference, area, and spherical area, how long do you think it will take you to find them all out?

This is where the circle calculator saves the day. This highly simple to use tool simply needs you to type in the radius or the diameter (whichever you choose to go with). It gives you the answer to all the aforementioned questions in a jiffy.

Calculating circles in everyday life can be really tedious in the absence of a circle calculator. Although professionals of different fields are well aware of the properties of a circle yet they prefer to use a circle calculator for real-world applications. They go through big calculations on a daily basis so it becomes even more critical for them to do quick and accurate calculations. For example, automobile engineers do it to calculate the wheels' circumference of trains, cars, etc. Space scientists do it when artificial satellites are launched in orbits of certain circumference. Making of wheels, bridges, car steerings, and properties like stadiums, everything becomes a reality after someone goes through huge and countless calculations to plan and execute things.

In astronomy spherical calculations are also done in order to do various planetary studies. The 3d version of circles is called sphere. Astronomers do sphere calculations to know the circumference of planets and compare their relative sizes. To calculate the properties of a sphere you can use a sphere calculator.

To sum it up, a circle calculator can be termed as a simple yet highly efficient tool for various day-to-day calculations, including, but not limited to homework, tests, quick math. No matter what your purpose is, you can do automatic calculations of a circle by entering one of the circle values and save a lot of your time that goes on manual calculations. If you have the radius, you can get the diameter, circumference, and area in less than a second, and if you have the circumference, you can get other variants as quickly as you want. That's how a circle calculator works and simplifies calculations of day to day life.

You may also find the following Math calculators useful.

- Ratio Division Calculator
- Round to Nearest Multiple Calculator
- Equivalent Ratio Calculator
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- Fraction Calculator
- Angle Between Two Vectors Calculator
- Recurring Decimal to Fraction Calculator
- Ratio Calculator
- Bilinear Interpolation Calculator
- Mass, Density and Volume Calculator
- Cylinder Calculator
- Sig Fig Calculator