\(a,b,c-lengths\ sides\ of\ a\ triangle,\ then:\\\\a+b > c\\a+c > b\\b+c > c\\\\if\ a\leq b\leq c\ then\ a+b > c\\------------------------\\a=6;\ b=9\to a+b=6+9=15\ then\ c=10\ or\ c=12\\\\a=6;\ c=9\to b=4\ because\ a+b=6+4=10 > 9\\a=6;\ c=9\to b=7\ because\ a+b=6+7=15 > 9\\\\Answer:A.10;\ B.7;\ C.4;\ F.12\)
