Answer:
any idea about the length of the box
Sin 3pi/4 is angle 135 degrees or 45 degrees below 180 degrees. Hence it's opposite side is 1 and adjacent is 1, implying the hypothenus is sqrt(2). Hence
Sin 3pi/4 = 1/sqrt(2). Now multiply by sqrt(2)/sqrt(2) to get:
[1/sqrt(2).] * [sqrt(2)/sqrt(2)] = sqrt2)/2
Not enough information to actually do the problem, please provide more.
The answer to this question is not rational