Final answer:
The smallest increment on a centimeter ruler with detailed markings is 0.1 cm, which allows for measurements to include a certain tenths digit and an estimated hundredths digit.
Step-by-step explanation:
The smallest increment on the centimeter portion of a ruler is typically 0.1 cm, which is equal to 1 millimeter (mm). Rulers designed with more precise measurements include marks for tenths of a centimeter, allowing for greater accuracy when measuring objects.
If a ruler has tick marks that represent 0.1 cm, then the object being measured can have its length reported with a tenths digit for certain and an estimated hundredths digit. For example, if an object's length is somewhere between 1.3 cm and 1.4 cm on the ruler, and it appears to be about six-tenths of the way between these two marks, the length can be estimated to be 1.36 cm.
Between each 0.5 cm line, there are four additional lines that denote the millimeter marks. There are a total of 10 lines per centimeter, with the 0.5 cm line acting as the 5 millimeter mark, making each centimeter 10 mm long. There are 300 millimeter marks on a 30 cm ruler.