You could describe the eighteenth century both ways. If you were speaking of, say, an event in ancient Egypt, you would say 1776 BC. If you were speaking of something such as the American Revolution, you would say 1776 AD. BC is the same as BCE and AD is the same as CE.
The year 1500 BCE falls within the 16th century BCE. The centuries are counted backward in BCE (Before Common Era) dating, so the 1st century BCE spans from 100 BCE to 1 BCE, making the 16th century BCE cover the years from 1600 BCE to 1501 BCE. Thus, 1500 BCE is the last year of the 16th century BCE.
88 BCE is in the first century BC or BCE.
20th Century BCE.
The year 3000 BCE falls in the 30th century BCE, as the centuries are counted backward before the common era (CE). Each century consists of 100 years, so the 30th century BCE spans from 3100 BCE to 3001 BCE. Thus, 3000 BCE is the last year of the 30th century BCE.
The year 2737 BCE falls within the 28th century BCE. Centuries are counted backward in the BCE (Before Common Era) system, so the 28th century BCE includes the years from 2800 BCE to 2701 BCE. Therefore, 2737 BCE is part of this earlier century.
The 13th century BCE.
The 4th century BCE.
The 14th Century BCE.
88 BCE is in the first century BC or BCE.
20th Century BCE.
Third century BCE
5721 BCE is the 58th century BCE.
5th Century BCE - in 490 BCE.
2012 BCE falls within the 21st century BCE. The centuries are counted backward from the year 1 CE, so the 21st century BCE includes the years 2100 BCE to 2001 BCE. Therefore, 2012 BCE is part of that range.
301
16th-century B.C.E. and 1550 B.C.E. is 50 years. The entire timeframe of 1501 B.C.E to 1599 B.C.E. is known as the 16th century. This would be true for each and every century.
The 20th century.