Describe how you would transfer a surface bearing down a shaft and set out a line underground in the same direction. Two plumb lines A and B in a shaft are 8.24 m apart and it is required to extend the bearing AB along a tunnel. A theodolite can only be set up at C 19.75 m from B and a few millimetres off the line AB produced. If the angle BCA is 09'54" what is the offset distance of C from AB produced?