for a triangle, there is a proven inequality that states that, the sum of the lengths of any two sides must be greater than or equal to the length of the remaining side
21 + 37 >= 15
58 >= 15
21 + 15 >= 37
36 >= 37
37 + 15 >= 21
52 >= 21
We can see that the second inequality doesn't comply, thus there is not such triangle.