in a 45 45 90 triangle the sides are x by x by xsqrt(2) respectively
therefore xsqrt(2) = 2 [the 2 that was mentioned in the question]
solving for x
x = 2 / sqrt(2) = sqrt(2) [after rationalizing the denominator]
x = sqrt(2) is now our side length
Area of Square = (side length)^2
so the Area of this Square = (sqrt(2))^2 = 2
therefore your answer is 2
