So the way you would find it is a ratio.
1.

2. =(6)(17)/(2.5)
3. =102/2.5
4. =40.8
So the building would be 40.8 feet tall.
The decimal for this would be 7.575
Hope this helped :)
Answer:
35
Step-by-step explanation:
Alright this is like a linear pair. All three angles add up to 180; so this is the set up:
40 + 2x + 30 + 40 = 180
2x + 110 = 180
2x = 70
x=35