Mathematics in Ancient and Medieval India c6.s2.67

c6.s2.67

When an *Adhyardhā* brick ( one and half times of a square i.e. a rectangular brick ) is cut along its two diagonals, it gives rise four triangular pieces two equal larger known as *Dīrghapādyā* bricks [ No. 13(1) ] and two equal smaller known as *Śulapādyā* bricks [ No. 13(2) ]. When a *Dīrghapādyā* having a triangular face ABC ( See Fig. 9 ) is cut into two equal halves by cutting along the perpendicular line from the vertex A to the base of its tringular face, it gives a brick with the face of a right-angled triangle ABC(Fig. 9). Similarly when a *Śulapādyā* brick having a triangular face ACD ( Fig 9 ) is divided into two equal halves by cutting it along the perpendicular line from the vertex A to the base of its triangular face, each gives a brick having a face of the shape of a right-angled triangle A F D. If a brick having the face of a shape of a right-angled triangle derived from *Dīrghpaādyā* or *Śulapādyā* (brick No. 14 or 15) be joined to a similar one derived from the *Pañcamī* along the sides of equal length [vide No. 10(1)] it gives rise to a brick [No. 16] whose face is represented by a scalene triangle PFC (Fig. 10).