Arc area formula How to calculate the area of Arc? (in the case of chord height, chord length and height)
This can be derived
The circumference of a circle is the product of the diameter and the circumference, and the corresponding center angle is 360 degrees;
The arc length of an arc is: the quotient of the center angle of the arc and 360 degrees, and then the product of the circumference of the circle
If the diameter D, the center angle α corresponding to the arc and the circumference π, the arc length formula is as follows:
l=πDα÷360