If you're asking what I think you are, whcih is basically how do you work out the circumference of a circle, it'll be Pi multiplied by the twice the radius of the circle. In your exaple your asking for quater of the circumference so it'd be:
(Pi x 2r)/4
(3.14159 x 2 x 3437.74)/4 = 5399.989
Or you could be asking a different question, in which case I don't have a clue what you're on about.