Answer:

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
.
Using the sine ratio, we obtain;

The length of the opposite side is 
We substitute the given values to obtain;


We cross multiply to obtain;


Therefore the correct answer is C.
20-3h=2=>3h=20-2=18=>h=18/3=6
Answer:
The answer is D
Step-by-step explanation:
Answer:
X = 116
Step-by-step explanation:
Total heptagon angle = 900
124 + 120 + 122 + 136 + 144 + 138 = 784
900 - 784 = 116