Answer: Mine A
Step-by-step explanation: Mine A is further underground because elevation means height and when it’s shows a number that is negative that means underground. 225 is greater than 223. So Mine A is further underground.
Step-by-step explanation:

That's an expression, so the only thing you can do is simplify it, but that already looks simplified.
Solution :
Given that :
The radius of circle A = 6 cm
The radius of circle C = 4 cm
In circle A

The length of arc EF = 

= 14.653 cm
In circle C

The length of arc GH = 

= 9.769 cm
Therefore,
The length of EF is 14.653 cm
The length of GH is 9.769 cm
The length of EF is 1.5 times the length of GH
i.e. 14.653 = 1.5 x 9.769
14.653 = 14.653
Hence proved.