The ancient Egyptians applied their knowledge of astronomy in multiple ways.
-They built the pyramids, using the stars and the alignment of the constellations to align the pyramids with cardinal points and to serve as a marker for the pharaoh's tomb.
-They developed a calendar based on the cycles of the sun, the moon, and the stars.
-They wrote medical textbooks, in which they used astronomical knowledge to predict the floods of the Nile River and to time the planting and harvest of crops.
-They created a process for embalming, in which they believed that the soul would journey through the afterlife guided by the stars and the night sky.
All of the above statements are true, the ancient Egyptians applied their knowledge of astronomy in multiple ways and not just building the pyramids.