Complete the number analogy: 43 : 49 :: 62 : ?

The two digits are added and the total is squared. For 43 that is 4 + 3 = 7 and $7\times 7=49$; for 62 it is 6 + 2 = 8 and $8\times 8=64$. The trap 12 is the product of the digits, and it looks convincing because $6\times 2=12$ is also what $4\times 3$ gives — yet the first pair answers 49, not 12. 36 squares only the leading digit, which would have made the first term 16, and 26 merely turns 62 round, which on the first pair would have given 34.