Hello!
The answer is:
The shadow is 173.20 feet
Why?
To solve the problem, we need to calculate the projection of the building's shadow over the ground.
We already know the height of the building (100 feet), also, we know the angle of elevation (30°), so, we can use the following formula to calculate it:
![Tan(\alpha)=(y)/(x)=(height)/(x)\\\\x=(height)/(Tan(\alpha) )](https://img.qammunity.org/2020/formulas/mathematics/middle-school/kgabbrgbr6aeqw007iarn6y6gvmbmow99x.png)
Now, substituting the given information and calculating, we have:
![x=(height)/(Tan(\alpha) )](https://img.qammunity.org/2020/formulas/mathematics/middle-school/y7iddg92zlmt46ea0p58x2ptgovh97u21h.png)
![x=(100feet)/(Tan(30\°) )=173.20feet](https://img.qammunity.org/2020/formulas/mathematics/middle-school/e844n5v9ezapgcs19g0r7mpf8plp52kkkk.png)
Have a nice day!