Question

what did ptolemaic and copernican models have in common? i dont know yet all orbits were elliptical. planets had epicycles. orbits of inner planets were circular, outer orbits of all planets had epicycles. all orbits were circular.

Explanation:

Both the Ptolemaic (geocentric) and Copernican (heliocentric) models assumed planetary orbits were fundamentally circular. While the Ptolemaic model used epicycles extensively and Copernicus reduced their number, both retained circular motion as the primary orbital path (elliptical orbits were later introduced by Kepler).

Answer:

All orbits were circular.