If we tell you that there is a relation between the numbers and letters in the given figure, can you analyze it and find the missing letter in the last box ?

The missing letter in the last box is Z.

Denote each alphabet to the corresponding number. For example, A = 1, B = 2, C = 3 and so on. Now you will find that the center digit is actually the product of the alphabets on both sides. In such case, the missing letter is Z.

=>G(7) * Z(26) = 182