Mathematics in Ancient and Medieval India c8.s3.125

c8.s3.125

*Lemma 1.* Let P, Q be points on the tangent at A to a circle of unit radius, whose centre is 0; let OP meet the circle in p. If m is the foot of the perpendicular from p to OQ, (Fig. 25) pm is given by, $pm = PQ/OP.OQ$