One option is to find a description of the model of the monitor, TV or laptop. To do this, go to the manufacturer website of your device and locate the products your model. In its technical characteristics will be required to indicate the size of the display, which is generally measured in inches (for example, 14”, 15,4”, 17”, 21” etc.). If you can't find the manufacturer's website, go to any major online store for household and computer equipment and view information about the device in the description of the model.
Another way – armed with a tape measure, to measure the screen. Its size made to measure diagonally. Attach a tape measure to the workspace screen and measure the distance from the lower right corner to upper left, or Vice versa. If roulette has no inch scale, divide the resulting figure by 2.54 (1 inch = 2.54 cm) and you get the size of the screen in the conventional measurement. For example, measurements showed that the diagonal of the screen is 39,11 see When dividing that figure by 2.54, you will learn that the size of the screen is 15.4”.
Instead of roulette you can use a tailor meter long ruler.