PIXEL DIMENSION . . .

PIXEL DIMENSIONS are the horizontal and vertical measurements of an image expressed in pixels. The pixel dimensions may be determined by multiplying both the width and the height by the dpi. 

An 48" x 32" document that is scanned at 72 dpi has the

pixel dimensions of 3456 pixels (48" x 72 dpi) by 2304 pixels (32" x 72 dpi).

A digital camera will also have pixel dimensions, expressed as the number of pixels horizontally and vertically that define its resolution (e.g., 2,048 by 3,072). 

Calculate the dpi achieved by dividing a document's dimension into the corresponding pixel dimension against which it is aligned.

Pixels: Individual pixels can be seen by zooming in on an image.

RESOLUTION is the ability to distinguish fine spatial detail. 

The spatial frequency at which a digital image is sampled (the sampling frequency) 

is often a good indicator of resolution. 

This is why dots-per-inch (dpi) or pixels-per-inch (PPI) are common and synonymous terms used to express resolution for digital images. Generally, but within limits, increasing the sampling frequency also helps to increase resolution.

DPI refers to the number of printed dots contained within one inch of an image printed by a printer. PPI refers to the number of pixels contained within one 

the inch of an image displayed on a computer monitor.

PixelCalculator

16:9 Aspect Ratio Wide-Screen Tv - REFERENCE

This is the viewing area of the picture!
Screen Dimensions for 16:9 Aspect Ratio Wide-Screen Tv:

26" = 12.7 (H) x 22.7 (W)..........288.3 (sq.in.)
27" = 13.2 (H) x 23.5 (W)..........310.2 (sq.in.)
30" = 14.7 (H) x 26.1 (W)..........383.7 (sq.in.)
32" = 15.7 (H) x 27.9 (W)..........438.0 (sq.in.)
34" = 16.7 (H) x 29.6 (W)..........494.3 (sq.in.)
37" = 18.1 (H) x 32.2 (W)..........582.8 (sq.in.)
40" = 19.6 (H) x 34.9 (W)..........684.0 (sq.in.)
42" = 20.6 (H) x 36.6 (W).........754.0 (sq.in.)
43" = 21.1 (H) x 37.5 (W)..........791.2 (sq.in.)
44" = 21.6 (H) x 38.3 (W)..........827.3 (sq.in.)
45" = 22.1 (H) x 39.2 (W)..........866.3 (sq.in.)
46" = 22.6 (H) x 40.1 (W)..........906.3 (sq.in.)
47" = 23.0 (H) x 41.0 (W)..........943.0 (sq.in.)
50" = 24.5 (H) x 43.6 (W)..........1068.2 (sq.in.)
51" = 25.0 (H) x 44.5 (W)..........1112.5 (sq.in.)
52" = 25.5 (H) x 45.3 (W)..........1155.1 (sq.in.)
53" = 26.0 (H) x 46.2 (W)..........1201.2 (sq.in.)
55" = 27.0 (H) x 47.9 (W)..........1293.3 (sq.in.)
56" = 27.5 (H) x 48.8 (W)..........1342.0 (sq.in.)
57" = 27.9 (H) x 49.7 (W)..........1386.6 (sq.in.)
60" = 29.4 (H) x 52.3 (W)..........1537.6 (sq.in.)
61" = 29.9 (H) x 53.2 (W)..........1590.7 (sq.in.)
62" = 30.4 (H) x 54.0 (W)..........1641.6 (sq.in.)
65" = 31.9 (H) x 56.7 (W)..........1808.7 (sq.in.)
70" = 34.3 (H) x 61.0 (W)..........2092.3 (sq.in.)

Here is the formula...
For a Standard 4:3 screen:
Width = Diagonal X 0.8
Height = Diagonal X 0.6
SO, a 32 inch 4:3 screen is 25.6 inches wide and 19.2 tall.

For a 16:9 Widescreen:
Width = Diagonal X 0.87157552765421
Height = Diagonal X 0.490261259680549
SO, a 43 inch 16:9 screen is 36.6 inches wide and 20.6 inches tall.

SOURCE