Question 492919
We are looking at the hypotenuse of a 45 45 90 right triangle.
The formula for the hypotenuse is side s = s{{{sqrt(2)}}}.
Therefore, The formula for the side is s/{{{sqrt(2)}}}
This would evalute to (12){{{sqrt(2)}}}/2, or 6{{{sqrt(2)}}}.
to check, 6{{{sqrt(2)}}}^2 + 6{{{sqrt(2)}}}^2 = 12^2
72 + 72 = 144.
This does check, 
Cleomenius.