We present five different solutions and outline a sixth and seventh one. In what follows, let a=BC, b=CA, c=AB as usual, and denote by r and R the inradius and circumradius. Let s=21(a+b+c). In the first five solutions we will only prove that ∠AIO=90∘⟹b+c=2a. Let us see how this solves the problem. This lemma implies that s=216. If we let E be the foot of I on AB, then AE=s−BC=72, consequently the inradius is r=972−722=65. Finally, the area is sr=216⋅65=14040.
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