Draw a figure!!!!!
The size of the balcony doesn't matter.
Based.on the information in the problem, I would ignore the difference in ht from the the "shore" to the base of the building. Then you are asking for length of one leg of a right triangle which has the other leg 8000 miles and hypotenuse 8000 miles + 250 feet.
Use the Theorem of Pythagoras after you do some unit conversions!