Mathematics in Ancient and Medieval India c6.s10.9

c6.s10.9

(c) *Construction of a quadrilateral* – A quadrilateral can be constructed, i) by joining two scalene triangles of equal bases along their base, ii) by joining four such right-triangles in a way that each pair forms a scalene triangle with equal bases. Such pairs can be constructed by suitable selection of right-angled triangle whenever necessary and iii ) by joining four scalene triangles. The number ( iii ) is not dealt by the Hindu mathematicians, but the algebraical formulae for determining the values of the quadrilateral of number ( i ) and ( ii ) were reduced from the Pythagoras' theorem by Brahmagupta.¹ Brahmagupta's method of constructing a quadri-