Arc length, radius, and central angle calculator of a circle

Arc length = [radius • central angle]
Knowing these two quantities, we can calculate the other quantities.
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Arc length formula: n is the degree of the center angle, r is the radius, and α is the radian of the center angle. l=nπr÷180 or l=n/180·πr or l=|α|r

In a circle with radius R, because the arc length corresponding to the center angle of 360° is equal to the circumference C=2πR, the arc length corresponding to the n° center angle is l=n°πR÷180°.

In the radian system, if the center angle corresponding to the arc is θ, then there is the formula L=Rθ. The formula for the area of ​​a sector is S=LR/2, and the corresponding formula for calculating the area of ​​a sector is S=RRθ/2.

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

The vertex of the central angle of a circle is at the center of the circle, and the angle where the two sides of the angle intersect the circumference is called the central angle of the circle. The value range of the central angle ∠AOB is 0°＜∠AOB＜360°