Fiona's school is in the shape of a triangle, with three hallways connecting the corners. Fiona enters the building and walks 90 yards through the first hallway to the first corner. Then, she walks 60 yards through the second hallway to the second corner. A triangle is shown. The side lengths are 60 yards, 90 yards, and the question mark. The top point is labeled exit and the bottom right point is labeled entrance. The distance between exit and entrance is a question mark.

What are the possible lengths of the third hallway?