p = [tex] \frac{AB+BC+AC}{2} = \frac{26}{2} =13 (cm)[/tex] (p=semiperimetru)
[tex]A_{ABC} = \sqrt{p(p-AB)(p-BC)(p-AC)} [/tex] = [tex] \sqrt{13*5*1*7} = \sqrt{455} (cm) [/tex]
[tex]A_{ABC} = \frac{d(C;AB)*AB}{2} = \sqrt{455} cm.[/tex] => d(A;BC)=[tex] \frac{2* A_{ABC} }{AB} = [tex] \frac{2* \sqrt{455} }{8} = \frac{ \sqrt{455} }{4} [/tex] (cm²)
