Centimetres to inches
One centimetre is 0.393701 inches, because an inch is defined as exactly 2.54 centimetres. Divide centimetres by 2.54, or multiply by 0.393701. Thirty centimetres is 11.81 inches: very nearly, but not quite, the foot rule it sits next to in a drawer.
How to convert centimetres to inches
Inches are usually spoken in fractions rather than decimals, so 0.375 in is three-eighths and 0.8125 in is thirteen-sixteenths. To turn a decimal into sixteenths, multiply by 16 and round: 0.7 in becomes 11.2, so eleven-sixteenths is the nearest common mark on a tape measure.
Questions
Yes, since the 1959 international yard and pound agreement. Before that the US and UK inches differed very slightly, which mattered to machinists and nobody else.
70.87 inches, which is 5 feet 10.9 inches. Height is the most common reason people land on this page.
Convention. A screen size is the diagonal, so a 27-inch monitor is 68.58 cm corner to corner, not across.
Four inches, or 10.16 cm. A 16-hand horse stands 162.6 cm at the shoulder.