unit conversions in centimeters and pixels

1 centimeters equals how many pixels

The client asks the map to show a map of how many, and then design the problem.

The answer on the net is that the question is the wrong answer, or 1 centimeters equals 25 pixels.
I know this problem is related to the size of the screen, because my monitor is about 1 centimeters over 30 pixels.
The following calculations have been made to find out.

Hypothetical premise:
A. 1 inches is 25.4 millimeters.
B. A 19-inch screen indicates a monitor with a diagonal length of 19 inches.
C. Display resolution is 1024*768
D. display horizontal unit pixel distance to the same distance as the vertical unit pixel


Specific calculation:
1.19-inch screen
I used exactly the 19-inch widescreen flat panel monitor.
Give you the measure. Width 41.2 cm tall is about 26 centimeters.



First calculate the length and width of the display:
19 inches = 482.6 mm
1024*768
Set width to W, high to H
Then W:h=1024:768=4:3
w= (1024/768) H = (4/3) h
w^2+h^2 = (482.6) ^2
(16/9+1) * h^2 = 232902.76 mm^2
(25/9) * h^2 = 232902.76 mm^2
h^2 = 83844.9936 mm^2
H. = 289.56 mm
W. = 386.08 mm

1 pixel = (386.08/1024) mm. = 0.377031 mm
1 mm. = 2.6523 pixels
1 cm. = 27 pixels




2.15-inch screen
15 inches = 381.0 mm
(16/9+1) * h^2 = 145161.00 mm^2
h^2 = 52257.96 mm^2
h = 228.6 mm
W = 304.8 mm
1 pixel = (304.8/1024) mm. = 0.29765625 mm
1 mm. = 3.3595800524934383202099737532808
1 cm. = 34 pixels

3. N-inch screen
n inch = 25.4 * N mm
(25/9) * h^2 = (25.4*n) ^2 mm^2
h^2 = 25.4^2 * n^2 * 9/25 mm
H = 25.4 * N * 3/5 mm
= 15.24 * N mm
w = 20.32 * N mm
1 pixel = (20.32 * n/1024) mm = (0.01984375 * N) mm
1mm = (50.3937007/n) pixel
1 cm = (503.937007/n) pixel

4. Several common n values
15 inches: 1 cm = 34 pixels
17 inches: 1 cm = 30 pixels
19 inches: 1 cm = 27 pixels
20 inches: 1 cm = 25 pixels
22 inches: 1 cm = 23 pixels