Example Questions Using the Formula for Arc Length. The plural form is radii pronounced ray-dee-eye. Now arc length is given by th360 2Pr l.
In the figure above drag the orange dot around and see that the radius is always constant at any point on the circle.
If a triangle has side lengths a b and c then we can find the length of its circumradius using the following formula. Worksheet to calculate arc length and area of sector radians. Demonstration of the Formula. The result will be the radius.