Prove that in any triangle it holds that

where denotes the circumradius and the inradius.

**Solution**

Using the law of sines we have that

and if we denote the area of the triangle then

Thus,

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Prove that in any triangle it holds that

where denotes the circumradius and the inradius.

**Solution**

Using the law of sines we have that

and if we denote the area of the triangle then

Thus,