Turn it to the maximum volume.

4(a+b+c) = 56 ( 1)

2ab+2bc+2ac = 1 12 (2)

What is needed now is the root number (A 2+B 2+C 2).

Square (1) a2+b2+c2+2ab+2bc+2ac =196.

And then substitute into formula (2)

a^2+b^2+c^2+ 1 12 = 196

So the root number (A 2+B 2+C 2) = root number 84 = 2 root number 2 1.