Final answer:
To find the century of a given year, drop the last two digits of the year and add one. The year 1901 begins the 20th century. For years ending in '00', like 1900, they mark the end of a century, in this case, the 19th century.
Step-by-step explanation:
To find the century from a given year, you can use the rule that centuries are defined by the hundreds place of the year number plus one. However, for years ending in '00', it is that century exactly. For example, the year 1901 is used to determine the century it begins. Since 1901 is one year past 1900, we can consider it part of the 20th century. In this case, to find the century, you simply take the year, drop the last two digits, and add one, which would give you 19 + 1 = 20th century.
If the given year was 1900, it would be the last year of the 19th century, since it is not beyond the '00' year that typically characterizes the beginning of a new century.