7. A fireman is standing on top of a building 20.0m high. He finds that if he holds the hose so that water issues from it horizontally at 12.0m/s, the water will hit a burning wall of an adjacent building, at a height of 15.0m above the ground. What is the horizontal distance from the fireman to the burning wall? (12.1 Already solved)

8. The fireman in Exercise 7 wants the water from the same hose to reach the burning wall at the same level above the ground as he is standing. At what angle must he aim the hose relative to the horizontal? (27.7 degrees)

I can't figure out #8 - I keep getting 22 degrees and I can't explain this to my daughter!