9x2.54=22.86 cm

The diameter of a nine-inch cake is about 22.86 cm.

The British system is still in use, generally 1in = 2.54cm, and the caliber of gun bullets is usually in inches, such as 357sig (9.0678mm) of p228, m1911and S & (USP). W's M500 revolver (12.7mm) and Pfeifer Seelis's 0.60-inch revolver (the most powerful revolver at present).

In English, 12 inch is 1 foot, and 36 inch is 1 yard.

Inches (abbreviated as in. ) It means thumb in Dutch, and one inch is the length of thumb. Of course, the length of a person's thumb is also different. /kloc-In the 4th century, King Edward II of England promulgated the "standard legal inch". It is stipulated that the three largest wheat grains should be selected from the middle of the barley ear and arranged in a row one inch in length.