To set Trace 2 to zero at 75 yards we clicked on the Trace 2 window to bring it to the front, then we clicked on the Zeroed Rng data to select it and then we did a right mouse click to bring up the copy menu.

It would be easy to just enter 75, but sometimes it's quicker to just copy the value from one of the other two traces, which is what was done here...

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