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# Circle arc length, radius, center angle online calculator

Category:

Arc length =[Radius • Central angle] If you know two quantities, you can calculate other quantities.
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### App description

Arc length formula: $$l=(nπr)/180$$ or $$l=n/180·πr$$ or $$l=|α|r$$

n is the number of center angles, r is the radius, *α is the central angle of the arc.

In a circle with a radius R, since the arc length of the 360° center angle is equal to the circumference length $$C=2πR$$, the arc length of the n° center angle is $$l=( n°πR)/180°$$

In the arc system, if the central angle of the arc is θ, then there is a formula L=Rθ. The fan area formula S=LR/2, corresponding to the fan area calculation formula $$S=RRθ/2$$

In a circle, the line connecting the center of the circle and any point on the circle is called the radius of the circle. Usually represented by the letter r.

The apex of the central angle is on the center of the circle, and the angle at which the two sides of the corner intersect the circumference is called the central angle. The center angle ∠AOB has a value range of 0°<∠AOB<360°

### Usage example

Input data:

Calculate arc length

Center angle (radian): 45

Click "Calculate" to output data

Arc length is equal to: 225