Because the depression angle between the chimney and the building is 45 degrees (both sides of the right triangle are equal), we can know that the distance between the chimney and the building is equal to the height difference between the chimney and the building. At the same time, because the elevation angle from point C to the building is 60 degrees, it can be obtained that the height of the building is 2X.
9+Y=2X and 18.2+X=Y, X=27.2, Y=45.4,
Then, the chimney height is 45.4+9-1.8 = 34.6m (1.8m is the height of a standing worker).