History of Hindu Mathematics: A Source Book v2.c17.s16.23

v2.c17.s16.23

So, by the Addition Lemma, we get the roots corresponding to the interpolator 153 as (12, 45). The rule says, 'If the interpolator (of a Square-nature) be divided by the square of an optional number etc.' Now take the optional number to be 3, so that the interpolator may be reduced to 17. For 3² = 9 and 153/9 = 17. Therefore, dividing the roots just obtained by the optional number 3, we get the required roots (4, 15).