iti voi explica ex 9)
a)
P=a+b+c=65. ( unde a,b,c sunt lat triunghiului)
{a;b;c} dp {2;5;6} => a/2=b/5=c/6=k => a=2k ; b=5k ; c=6k
P=2k+5k+6k=13K=65/:13=> k=5 => a=10 ; b= 25; c=30
b)
P=a+b+c=270
{a;b;c} dp {3;4;5} => a/3=b/4=c/5=k => a=3k ; b=4k; c=5k
P=3k+4k+5k=12k=270=> k=22,5 => a=67,5 ; b=90 ; c=112,5;