He retired in the methodology used to calculate the area under a curve, parabola, with a total of infinite series. And estimates to the nearest of the oar.
He used the method of exhaustion to calculate the area under the curve is a parabola with the summation of an infinite series. The closest approximation of the pie.
He used the method of retirement in the calculation of area under the curve of parabola by finding the sum of infinite series. Series And the closest of PI.