Exercising the circumference

Please check my maths. I walk around a 3 metre diameter pool for 100 laps. That means I journey 9.42 metres a circuit as that's the pool's circumference. But since I walk within that circumference my real arc is closer to a diameter of 2 metres. That means I travel 6.28 metres each lap.
Circumference = Pi (3.14) times Diameter (C=pD)
So how far do I travel in total?

I get 628 metres. --dragging myself through the water in an upright stride...creating my own rotor with its own momentum.

And thats' what I do in the pool each day.
....when I can manage it.