In Fig. 10.74, CP and CQ are tangents to a circle with centre O. ARB is another tangent touching the circle at R. If CP = 11 cm and BC = 7 cm, then find the length of BR.

Given:


CP = 11 cm


BC = 7 cm


Property: If two tangents are drawn to a circle from one external point, then their tangent segments (lines joining the external point and the points of tangency on circle) are equal.


Using the above property,


CP = CQ = 11 cm (tangent from C)


BQ = BR (tangent from B)


And,


AP = AR (tangent from A)


Now,


BR = BQ = CQ – CB


= 11 cm – 7 cm


= 4 cm


Hence, BR = 4 cm


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