Marinada '21

[lang=hr] Sad kad je konačno uspio nacrtati taj trokut koji je nazvao $\triangle ABC$, Vedran dodaje proizvoljnu točku $P$ unutar njega te promatra izraz $PA^2+PB^2+PC^2$. Pomozite mu naći minimum tog izraza! (Opet želi zaokruženo na pet decimalnih mjesta.) [/lang] [lang=en] Now that he has finally managed to draw that triangle which he has labeled $ \triangle ABC $, Vedran has added an arbitrary point $ P $ inside of it and observes the expression $ PA ^ 2 + PB ^ 2 + PC ^ 2 $. Help him find the minimum of that expression. (Again, he wants the result rounded to five decimal places.) [/lang]