What 8 by 8 in diagonal inches?

Pythagoras developed the method to solve this- A squared plus B squared equals C squared. A squared= 8x8, added to B squared (also 8x8) So that is 64+64 or 128. So 128 is line C squared. Find the square root of 128, and you have C, which is the diagonal. (Hint- it is 11.31)