Question

A student used the above ruler to measure the length of a nail. The length of this nail, according to the precision of the ruler, is ________.

1) 2 cm
2) 3 cm
3) 4 cm
4) 5 cm

Answer 1

Using a ruler without millimeter markings, the length of the nail can be estimated as 2.5 cm, due to the uncertainty of the exact tenths digit.

Step-by-step explanation:

The length of the nail, according to the precision of the ruler, is best estimated as 2.5 cm. This is because although the exact tenths digit can be uncertain without millimeter markings, we can estimate the measurement to the nearest half centimeter based on the given rulers and the example provided. While on a ruler with millimeter markings, the measurement could be more precise (e.g., 2.54 cm or 2.56 cm), on a ruler without these fine markings, estimating to the nearest half centimeter (e.g., 2.5 cm) is reasonable.