History of Hindu Mathematics: A Source Book v1.c8.s12.1

v1.c8.s12.1

**Terminology.** The Hindu name for the Rule of Three terms is *trairāśika* ("three terms," hence "the rule of three terms"). The term *trairāśika* can be traced back to the beginning of the Christian era as it occurs in the Bakhshâlî Manuscript,¹ in the *Âryabhaṭîya* and in all other works on mathematics. About the origin of the name Bhâskara I (*c.* 525) remarks:² "Here three quantities are needed (in the statement and calculation) so the method is called *trairâśika* ("the rule of three terms")."