The arc length of a semicircle is half the circumference of the full circle. Well of course it is but its nice that we came up with the right answer. So in summation The formula for arc length is.
Arc Length The arc length is.
An arc length is just a fraction of the circumference of the entire circle. Again when working with p if we want an exact answer we use p. S a b 1 d y d x 2 d x. S 3 2 1 So the arc length between 2 and 3 is 1.