I don't think you mean a "perfect" square. A perfect square is a whole number
that is the product of a smaller whole number multiplied by itself.
1, 4, 9, 16, 25, 36, and 49 are the perfect squares that are less than 50.
I think you mean a "magic" square ... one in which each row, each column,
and each diagonal, all add up to the same number. If that's what you mean,
then the answer to the question is "no". Magic squares are always square.
That is they always have the same number of rows and columns. So the
number of 'cells' in a 'magic' square is always a 'perfect' square.
50 isn't a perfect square, so you can't make a magic square with it.