The height is 1943.8 feet. easiest way to do this is draw a little diagram. Draw the building and the unknown height can be "x". We know a 1000 feet away from the base of the building, the angle between the ground and top of the building is 11 degrees. If you draw this, you can see that you can use the tan function to find the missing "x". tan (angle) = opposite side/adjacent side. So tan(11) = x/1000. Isolate for x and you get 1943.8 feet