Aici poti folosi formula lui Heron.
Fie a = 10 cm, b = 25 cm si c = 26 cm.
[tex]A_{ABC}=\sqrt{p*(p-a)(p-b)(p-c)}=\sqrt{\frac{a+b+c}{2}*(\frac{a+b+c}{2}-a)(\frac{a+b+c}{2}-b)(\frac{a+b+c}{2}-c)}=\sqrt{\frac{10+25+26}{2}*(\frac{10+25+26}{2}-10)(\frac{10+25+26}{2}-25)(\frac{10+25+26}{2}-26)}=\sqrt{30,5*20,5*5,5*4,5}=\sqrt{15474,9375}=124.3983cm^{2}[/tex]
