There is no question. So okay :)
5 and up, raise it up
4 and below, keep it low!
7.0
For this you will use the tangent function. You have the adjacent side and have to find the opposite side.
tan x = opposite/adjacent
tan 25 = x/15
15 (tan 25) = x
6.9946 = x
So the boat is approximately 6.9946 m away from the lighthouse.