Answer
$\phi=47 ^{\circ}$
Work Step by Step
First, draw each of the diagonal. The length of 1/2 the diagonal is 5.5 in. Since the length of the side is 6 in, we find:
$ \phi /2 = cos^-1(5.5/6)$
Note that the angle is divided by two since this represents only 1/2 of the angle. Thus, we find:
$\phi=47^{\circ}$
