In a 45-45-90 right triangle, the properties of the triangle are such that it has two equal angles of 45 degrees and a right angle of 90 degrees. This makes the triangle isosceles, meaning that the two legs are of equal length.
Since both legs of the triangle are congruent, the ratio of the length of one leg to the length of the other leg is simply the ratio of the same number to itself.
Therefore, the ratio is [tex]\( 1:1 \)[/tex].
Thus, the answer is:
D. [tex]\( 1:1 \)[/tex]
