Final answer:
The Greek Drachma is the 19th-century Hellenistic monetary unit that became equivalent to 100 lepta.
Step-by-step explanation:
In the 19th century, the ancient Hellenistic monetary unit that became equal to 100 lepta was the Greek Drachma. The Drachma is a significant historical currency which not only played a critical role in the ancient economy and trade but also served as the foundational system that inspired numerous other currencies. For reference, the Drachma is often mentioned alongside other historical currencies such as the German Mark, French Franc, and Italian Lira.