34: compounds 29. noble gases 39. electrons 40. non-metal
Answer:
Length of the tunnel is 51.7 meters
Step-by-step explanation:
We are given that,
The surveyor is located 54 meters from one entrance at an angle of 56°.
The surveyor is located 31 meters from one entrance at an angle of 13°.
Let the length of the tunnel = x meters
So, using the law of cosines, we get,

i.e. 
i.e. 
i.e. 
i.e. x = 51.7 meters
Hence, the length of the tunnel is 51.7 meters