Answer:
Height of the building = 18.3 ft
Explanation:
Let the height of the building = x ft
From the picture attached,
A boy is standing on the building at a point A, car is at a point B and a bird is flying at C.
Applying Pythagoras theorem in ΔABD to find the distance AD.
AB² = BD² + AD²
AD = 

 = 

 = 

 = 15 units
Now from ΔACD,
tan(70)° = 

1.22196 = 

x = 15 × 1.22196
x = 18.33
 ≈ 18.3 ft
Therefore, height of the building is 18.3 ft.