In the first image the x would be 127 because 8.3 times 8.3 is 68.89 and 15.2 time 15.2 is 231.04 so 231.04 - 68.89 is 162.15 and it square root is more or less at 12.7
In the second the x is 16.2 because 2.9 times 2.9 is 8.41 and 16 times 16 is 256 so 256 + 8.41 is 264.41 and it square root is more or less at 16.2