Inches and centimetres measure the distance between two points. You may need to convert from centimetres to inches if you are building a model that requires you to cut a board a certain length in centimetres but you only have a ruler that measures in inches. Centimetres and inches are related by a conversion factor: 2.54 centimetres per inch. This conversion factor makes it a simple matter to convert centimetres to inches.
Write down the quantity 116 centimetres.
Divide by 2.54 centimetres per inch to obtain an answer of 44.67. Since you are dividing centimetres by a factor with units of centimetres per inch, the centimetres will cancel so that you will be left with inches.
Go to an online conversion site (see Resources), enter the quantity "116" and click on "Go". The online calculator gives you the same result.