Answer:
[tex]\boxed{C.\:\: 600\:feet}[/tex]
Step-by-step explanation:
The tunnel, the ground and the depth of the tunnel form a right angle triangle.
The length of the tunnel is the hypotenuse of the right triangle that has been formed.
Let the length of the tunnel be [tex]m\: feet[/tex].
Using the sine ratio, we obtain;
[tex]\sin(30\degree)=\frac{Opposite}{Hypotenuse}[/tex]
The length of the opposite side is [tex]300\:feet[/tex]
We substitute the given values to obtain;
[tex]\sin(30\degree)=\frac{300}{m}[/tex]
[tex]\Rightarrow \frac{1}{2}=\frac{300}{m}[/tex]
We cross multiply to obtain;
[tex]m=300\times2[/tex]
[tex]m=600\:feet[/tex]
Therefore the correct answer is C.
