Mathematics in Ancient and Medieval India c8.s2.16

c8.s2.16

*Later Approximation*—After Bhāskara II (c. 1150 A. D.), it is Nīlakaṇṭha who began to realize the irrationality of π. The reason for irrational value of π, according to Nīlakaṇṭha is given as follows : “If the diameter, measured with respect to a particular unit of measurement, is commensurable with respect to that same unit of measurement, the circumference is in-commensurable; and if with respect to any unit the circumference is commensurable, then, with respect to the same unit, the diameter is incommensurable”.³ He therefore proceeded to calculate the value of π in terms of series.