I'm not sure if that's what you mean, but the difference between 6010 and 5060 is 950, so to find a number in a halfway between them I divided 950 by 2 (which is 475) and added it to 5060 (or substracted from 6010 - it's the same). Next I added the same number (475) to 6010. So finally it would like like this:
The triangle inequality requires the third side be in the range .. 12 -4 ≤ third side ≤ 12 +4 .. 8 ≤ third side ≤ 16 . . . . . . . . . your answer is the number(s) in this range
_____ Some define the triangle inequality using < rather than ≤. Be careful here.
