Question

21:145::13:962::61:257::51:?​

Answer 1

Answer:

226

Step-by-step explanation:

21:145::13:962::61:257::51:?​

21 : 145

21 - 12

12² = 144

144 + 1 = 145

13 : 962

13  - 31

31² = 961

961 + 1 =  962

61 : 257

61  - 16

16² = 256

256 + 1 = 257

51 : ?

51 - 15

15² = 225

225 + 1 = 226

Rule is

ab  : c

=> (ba)² + 1 = c