Geron formulasi — uchburchakning yuzi uchala tomoni orqali ifodalanuvchi formula: S = p ( p − a ) ( p − b ) ( p − c ) {\displaystyle S={\sqrt {p(p-a)(p-b)(p-c)}}} , bunda S — uchburchak yuzi, a, b va c — tomonlari, Sp — yarim perimetri ( p = a + b + c 2 {\displaystyle p={\frac {a+b+c}{2}}} ).