Final answer:
The subject of this question is Arts. The popular dance introduced to ballrooms in Prague in the 1830s could be the polka, a half-step dance performed in 2/4 time signature.
Step-by-step explanation:
The subject of this question is Arts. The question is asking about a popular dance in the first part of the century that was introduced to ballrooms of Prague in the 1830s.
Based on the provided information, this dance could be the polka. The polka was a popular dance in the 19th century and was introduced to ballrooms in Prague during the 1830s. It is a half-step dance performed in 2/4 time signature.
Other examples of popular dances in the first part of the century include the waltz, tango, and foxtrot.