ab=15
bc+ca=25
va rog mult

Bc^2=ab^2+ac^2 ( teorema lui pitagora)
Ac^2=bc^2-ab^2
Ac^2=bc^2-225
Ac^2=(25-ac)^2-225
Ac^2=625-50ac+ac^2-225
50ac=400
Ac=8