186 GANITASĀRASANGRAHA. 6. (The curvi-linear area may be) a circle, a semicircle, an ellipse, a conchiform area, a concave cicular area, a convex circular area, an out-lying annulus or an in-reaching annulus. 13 Doe 12 Kambnkäyrtta conchiform Nimnavrtta concave Unnatavrtta convex circular area. circular area. 15 area O T Bahıścakravalavrtta Out-lying annulus. 14 16 O Antascalravalavrtta In- reaching annulus. From a consideration of the rules given for the measurement of the dimen- sions and areas of quadrilateral figures, it has to be concluded that all the quadrilateral figures mentioned in this chapter are cyclic. Hence an equilateral quadrilateral is a square, an equidichastic quadrilateral is an oblong, and equi- bilateral and equi-trilateral quadrilaterals have their topside parallel to the base
