Question 389458
Let the length of the base be 4 inches, the width of the base be 3 inches, and the height, 2 inches.  Then the measure of the diagonal of the 2x 3 face is {{{sqrt(13)}}}, the measure of the diagonal of the 3x 4 face is 5, and the  measure of the diagonal of the 2x 4 face is {{{2sqrt(5)}}}.  The three diagonals form a triangle.  Then from the cosine law, 

{{{20 = 25 + 13 - 2*5*sqrt(13)*cos(theta)}}}
===>{{{ -18 = -10sqrt(13)cos(theta)}}}
===>{{{cos(theta) = (9sqrt(13))/65}}}
===> {{{theta = 60}}}degrees, to the nearest degree.