If 23=31, 34=52, 56=16 then 78=?

Question

If
51 x 51 = 26 01
52 x 52 = 27 04
53 x 53 = 28 09
54 x 54 = 29 16
55 x 55 = 30 25
56 x 56 = 31 36
then
57 x 57 = ?? ??

Answer 1

square of first digit+square of second digit and reversing the digit we get answer

23 = 31
(2*2)+(3*3) = 13 and reversing the digit 31
similarly
34 = 52
(3*3)+(4*4) = 25 and reversing the digit 25

56 = 16
(5*5)+(6*6) = 61 and reversing the digit 16
so
78 = 311
(7*7)+(8*8) =113 and reversing the digit 311