+1 vote
in JEE by kratos

If d1,d2,d3 are the diameters of the three escribed circles of a triangle, then d1d2 + d2d3 + d3d1 is equal to

(a) Δ2

(b) 4s2

(c) 2Δ2

(d)4Δ2

1 Answer

+5 votes
by kratos
 
Best answer

Correct option (b) 4s2

r1r2 + r2r3 = 4s2

4r1r2 + 4r2r3 + 4r3r1 = 4s2⇒ 4d1d2 + 4d2d3 + 4d3d1 = 4s2

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