The inradius of a circle inscribed in an isosceles triangle

MATHEMATICS · Single correct · A Level · Mathematics · Trigonometry · Trigonometry

Problem

The inradius of a circle inscribed in an isosceles triangle, one of whose angles is 2π3\frac{2\pi}{3}, is 3\sqrt{3}. Then the area of the triangle, in square units, is (1) 434\sqrt{3} (2) 12−7312-7\sqrt{3} (3) 12+7312+7\sqrt{3} (4) None of the above

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