Given that the gardener wants the number of trees in each raw to be equal to the number of rows, then let the number of in each row be x this means that the number of rows will be x.
Thus the total number of trees will be:
Total=(number of rows)*(number of trees in each row)
hence:
122500=x×x
122500=x²
hence
x=√122500
x=350
thus the number of rows will be 350 and the number of trees in each row will be 350