Type in the given rate: 3.5 inches per month. Next, realize you must convert "inches" to "cm," remembering that 1 inch = 2.54 cm (approximately). Make a conversion factor out of "1 inch = 2.54 cm" as follows: 1 = 2.54 cm / 1 inch. Multiply "3.5 inches per month" by this factor 2.54 cm / 1 inch. Note that "inches" will then cancel out, and your measurement will be in cm / month.
