In Fig. 8.48, POQ is a line. Ray OR is perpendicular to line PQ. OS is another ray lying between rays OP and OR. Prove that ROS = (QOS –POS.)

OR perpendicular to PQ

Therefore,


POR = 90o


POS + SOR = 90o [Therefore, POR = POS + SOR]


ROS = 90o - POS (i)


QOR = 90o (Therefore, OR perpendicular to PQ)


QOS - ROS = 90o


ROS = QOS – 90o(ii)


By adding (i) and (ii), we get


2ROS = QOS - POS


ROS = (QOS - POS)


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