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1900
Circumradius and Inradius
Editorial
geometrytrianglesincirclescirclestrigonometry
In triangle ABCABC, let RR be the circumradius and rr the inradius. Given that R=3rR = 3r, compute
cos⁡A+cos⁡B+cos⁡C.\cos A + \cos B + \cos C.
Express your answer as a fraction in lowest terms.

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