A tangent PQ at a point P of a circle of radius 5 cm meets a line through the centre O at a point Q so that OQ = 12 cm. Length PQ is :

A. 12 cm B. 13 cm


C. 8.5 cm D. 119 cm.


(D)

We know that the line drawn from the centre of the circle to the tangent is perpendicular to the tangent.


OP PQ


By applying Pythagoras theorem in ΔOPQ,



OP2 + PQ2 = OQ2


52 + PQ2 =122


PQ2 =144 - 25


PQ = cm.


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