math

a = {2, -1, 1};

b = {1, -3, -5};

c = {3, -4, -4};

p = a.Cross[b, c];

If [p ⩵ 0 && (a + b ⩵ c || b + c ⩵ a || c + a ⩵ b || a + b + c ⩵ 0) && (a.b ⩵ 0 || b.c ⩵ 0 || c.a ⩵ 0) ,

Print["Form a right angled triangle"] ,

Print["Doesn't Form a right angled Triangle"]]