What is the circumference of a circle if the radius is 4

If you need to solve some geometry exercises, this circumference calculator is the page for you. It is a tool specifically created to find the diameter, circumference and area of any circle. Read on to learn:

• What the definition of circumference is
• How to find the circumference of a circle
• How to convert circumference into diameter

As is the case with all of our tools, the circumference calculator works in all directions - it is also a circumference to diameter calculator, and can be used to convert circumference to radius, circumference to area, radius to circumference, radius to diameter (duh!), radius to area, diameter to circumference, diameter to radius (yes, again with the rocket science), diameter to area, area to circumference, area to diameter or area to radius.

If you want to draw a circle on the Cartesian plane, you might find this equation of a circle calculator useful.

The circumference of a circle is the linear distance of a circle's edge. It is the same as the perimeter of a geometric figure, but the term 'perimeter' is used exclusively for polygons.

Circumference is often misspelled as circumfrence.

The following equation describes the relation between the circumference and the radius R of a circle:

C = 2πR

Where π is a constant approximately equal to 3.14159265...

A similarly simple formula determines the relationship between the area of a circle and its radius:

A = π * R²

1. Determine the radius of a circle. Let's assume it's equal to 14 cm.
2. Substitute this value to the formula for circumference: C = 2 * π * R = 2 * π * 14 = 87.9646 cm.
3. You can also use it to find the area of a circle: A = π * R² = π * 14² = 615.752 cm².
4. Finally, you can find the diameter - it is simply double the radius: D = 2 * R = 2 * 14 = 28 cm.
5. Use our circumference calculator to find the radius when you only have the circumference or area of a circle.

If you wish to calculate the properties of a three-dimensional solid, such as a sphere, cylinder or cone, it's best to use our volume calculator.

You have probably noticed that, since diameter is twice the radius, the proportion between the circumference and the diameter is equal to π:

C/D = 2πR / 2R = π

This proportion (circumference to diameter) is the definition of the constant pi. It is used in many areas, such as physics and mathematics. For example, you can find it in the centrifugal force calculator.

To calculate the circumference, you need the radius of the circle:

1. Multiply the radius by 2 to get the diameter.
2. Multiply the result by π, or 3.14 for an estimation.
3. That's it; you found the circumference of the circle.

Or you can use the circle's diameter:

1. Multiply the diameter by π, or 3.14.
2. The result is the circle's circumference.

The circumference of a circle is the linear distance of the circle's edge. It is equivalent to the perimeter of a geometric shape, although that term perimeter is only used for polygons.

The first person to calculate the Earth's circumference was Eratosthenes, a Greek mathematician, in 240 B.C. He discovered that objects in a city on the Northern Tropic do not throw a shadow at noon on the summer solstice, but they do in a more northerly location. Knowing this, and the distance between the locations, he succeeded in calculating the Earth's circumference.

If you want to find the diameter from the circumference of a circle, follow these steps:

1. Divide the circumference by π, or 3.14 for an estimation.
2. And that's it; you have the circle's diameter.

To find the area of a circle from the circumference, follow these steps:

1. Divide the circumference by π.
2. Divide the result by 2 to get the circle's radius.
3. Multiply the radius by itself to get its square.
4. Multiply the square by π, or 3.14 for an estimation.
5. You found the circle's area from the circumference.

To find the radius from the circumference of a circle, you have to do the following:

1. Divide the circumference by π, or 3.14 for an estimation. The result is the circle's diameter.
2. Divide the diameter by 2.
3. There you go, you found the circle's radius.

• Calculate the circumference as 2 ⨉ radius ⨉ π.
• Calculate the circumference as diameter ⨉ π.
• Wrap a string around the object and measure the length of it.
• Use Omni's circumference calculator.

The formula for the circumference, if the circle's radius is given, is:

Or if the circle's circumference is given:

You can estimate π as 3.14.

To calculate the circumference of a circle with a radius of 1 meter, simply follow these steps:

1. Multiply the radius by 2 to get the diameter of 2 meters.
2. Multiply the result by π, or 3.14 for an estimation.
3. And there you go; the circumference of a circle with a radius of 1 meter is 6.28 meters.

To find the circumference of a cylinder, you have to be aware that a cylinder's cross-section is a circle. If you know the cylinder's radius:

1. Multiply the radius by 2 to get the diameter.
2. Multiply the result by π, or 3.14 for an estimation.
3. That's it; you found the circumference of the cylinder.

Or you can use the cylinder's diameter:

1. Multiply the diameter by π, or 3.14.
2. The result is the cylinder's circumference.

If you want to find the area of a circle with a circumference of 1 meter, do the following:

1. Divide the circumference by π. This is the circle's diameter, in this case, 31.8 centimeters.
2. Divide by 2. This result is the circle's radius of 15.9 centimeters.
3. Multiply the radius with itself, getting the square, in our case 256 cm².
4. Multiply by π, or 3.14 for an estimation.
5. That's it; a circle with a circumference of 1 meter has an area of 795.78 cm².

To find the radius of a circle with a circumference of 10 centimeters, you have to do the following:

1. Divide the circumference by π, or 3.14 for an estimation. The result is the circle's diameter, 3.18 centimeters.
2. Divide the diameter by 2.
3. And there you go, the radius of a circle with a circumference of 10 centimeters is 1.59 centimeters.

Since a circle's circumference is the linear distance of the circle's edge, it describes a length. Therefore, the most common units of a circle's circumference are millimeter, centimeter, meter for the metric system, and inch, feet, and yard for the imperial system.

The formula for circumference of a circle is 2πr. Since the radius is 4, the circumference is 8π or approximately 25.12 inches.

Here is the answer to questions like: how to find the perimeter of a circle with radius 4 cm?

Circle Calculator

Use the this circumference length calculator above to find the perimeter of a circle given its radius, or other parameters.

Here a three ways to find the circumference or perimeter of a circle:

Questions this calculator can answer:

• How to find the perimeter of a circle with a radius of 4 cm?
• A circle has a diameter of 8 cm. What is its circumference?
• If a circle has a area of 50.27 square centimeters. What is its perimeter?

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