Refer to the attached image.
Let the height of the Empire State Building = BC = 'x'
John is standing at distance from Empire State Building = AB = 1 mile
The angle of elevation = 11°
In triangle ABC,
Consider




x = 0.194 mile
Since 1 mile =5280 feet
So, x =

= 1024.32 feet.
So, the height of the Empire State Building is 1024.32 feet.