Answer:
sqrt(area)
Explanation:
As we have to find the length of the diagonal, we must knew that as all sides of the square are same in length so are the diagonals. This means that each of the four sides of the square and it diagonals are equal in length.
So a square has: length=breadth=diagonal
As Area= length*breadth
√area = length (as length = diagonal length)
So √area = diagonal length