Whoever worded this question is a sadist, however this is what i think it was asking lol
A right triangle is half the size of a square. So if its area is 12, the square is 24. If our squares sides are 6. If that is true or triangles outer sides are 6 as well. To summarise:
Your square has an area of 24. Your triangle an area of 12, and their sides are 6.