Geometry in Ancient and Medieval India c8.8

c8.8

It is interesting to find a distinction being made between the *caturaśra* and *catuṣkoṇa*. The accepted meaning of *asra* or *aśra* or *asri* is a corner and that of *caturaśra* a four-cornered figure which is a quadrilateral. But in the light of the passages in which this distinction occurs *asra* is perhaps to be taken to mean side. Dr. B. B. Datta following Weber translated *samacaturaśra* and *viṣamacaturaśra* as even and oblique square; and *samacatuṣkoṇa* and *viṣamacatuṣkoṇa* as even and oblique parallelogram.³ The occurrence of the word *koṇa* distinguished as equal and unequal, in such an early work as the *Sūryaprajñapti* indicates that the Indians had some conception of angles and that the word *koṇa* appearing in later works is of native origin and not an Indianisation of the Greek *gonia*. That the *viṣavacakravāla* (unequal circle, ellipse) should be distinguished from the *samacakravāla*, the equal circle is also interesting more especially when two perpendicular diameters distinguished as *āyāma* and *viṣkambha* are mentioned.¹ These, of course, are equal in a circle.