Puzzles - Missing letters puzzles

Answer

:

I

Explanation

:

As you move down, letters are written in alphabetical order, skipping any letters written with curved lines.

Answer

:

F

Explanation

:

Starting with the top segment of the top left square and moving clockwise around the other 3 squares, letters move through the alphabet in steps of 2, with the positions moving one place clockwise each time. Letters in the next segment of the top left square follow the same pattern, in steps of 3 letters etc.

Answer

:

D

Explanation

:

Starting with the bottom right letter and moving in a clockwise spiral around the diagram towards the centre, letters advance through the alphabet six letters at a time.