The area of the screen can be worked out using:
area = diagonal^2/(aspect+1/aspect)
so 4" = 10.16cm, the area = 10.16^2(16/9+9/16) = 44.1sqcm
area = x * y where x = aspect * y
so x = sqrt(area/aspect) = sqrt(44.1*9/16) = 4.98cm
y = 8.85cm
One of the recent stories, last week or two, gave away the dimensions of the "case." I used these measurements to verify that my project would work with the new phone. I can't look them up right now, but good luck with your project!