I'm not asking the diagonal values, but the length and breadth ones of the Nexus 7. And only of the LCD screen, not the entire hardware.
The screen size is 151mm * 94mm
You can always use some mathematics to obtain screen size:
X = sqrt ( Z^2 / (1 + (VR/HR)^2) )
sqrt = Square Root √‾‾‾
X = screen width
Z = diagonal screen size (7" for Nexus 7)
VR = vertical resolution
HR = horizontal resolution
which for Nexus 7, we have:
Z = 7" VR = 1280 HR = 800
X = sqrt ( 49 / 3.56)
X = 3.71 inches ~ 94mm
Y = (1280/800) * X = 1.6X
Y = 5.936 inches ~ 151mm
so we have 151mm x 94mm which Peanut has linked to.
So you want to know the display area ..
(A.) The non-masked (clear) area of the front face:
A simple metric ruler, and ASUS Nexus 7, gives you ..
Answer: 152mm x 95mm
(B.) The area of active pixels, on the IPS LCD display:
display pitch: 216 dpi (pixels per inch, leading edge to leading edge)
pixel size: 96% of pitch (guesstimate, without engineering drawings)
pixel geometry: square (identical height, width)
display size (in pixels): 1280 x 800
screen area: (mathematical)
=> (height - 1) x pitch + pixel_width by (width - 1) x pitch + pixel_width => (1279 x 0.1175 + 0.1128) by (799 x 0.1175 + 0.1128) => 150.40 by 94.00 mm
Answer: 150.4mm x 94.0mm
Actual diagonal width, for ASUS Nexus 7 display area:
=> square root ( height squared + width squared ) => square root ( 150.40 squared + 94.00 squared ) => square root ( 22,620.16 + 8,836 ) mm => 177.36 mm => 177.36 / 25.4 (convert to inches)
Answer: 177.4mm or 6.98 in
try downloading the Screeninfo app from the Google Play store for useful screen info. This works on any other Android device as well.