Final answer:
The ancient Egyptians used astronomy to develop a calendar system aiding in agricultural planning, align monumental structures for religious and ceremonial use, and conduct rituals at specific times.
Step-by-step explanation:
How did ancient Egyptians benefit from their study of astronomy? The ancient Egyptians benefited from astronomy by developing a calendar system. This system helped them predict the annual flood of the Nile River, which was crucial for agriculture. They observed the stars and mapped them, most notably the star Sirius, which heralded the inundation of the Nile. Astronomy also allowed them to construct monumental structures like the pyramids with precise astronomical alignments, enhancing their religious and ceremonial practices. Moreover, understanding celestial patterns was essential for certain religious beliefs and ensuring that rituals could be conducted at specific times of the year.