I am a bit out of touch with geometry since I've learned it many years ago during high school days. I just wanted clear off with the confusion that arose with this question.
I was expecting an answer like what was given by Viera Čerňanová.
You need no trig to answer this one. Just cut a right triangle off of the left side and past it to the right and you get a rectangle of base 4 with height < 6. B