Problem

Problem

A straight line intersects the three concentric circles at A,B,CA, B, C. If the distance of the line from the centre of the circles is s=Ps=P, prove that the area of the triangle formed by the tangents to the circle at A,B,CA, B, C is 12P⋅AB⋅BC⋅CA\frac{1}{2P}\cdot AB\cdot BC\cdot CA.

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