The average orbital distance of Mars is 1.52 times the average orbital distance of the Earth. Knowing that the Earth orbits the sun in approximately 365 days, time for mars orbit around the sun would be
684 days
Rmars=1.52×Rearth and Tearth=365 days
Use Kepler's third law to relate the ratio of the period squared to the ratio of radius cubed
T2marsT2earth=R3marsR3earth(Tmars)2=(Tearth)2×R3marsR3earth(Tmars)2=(365 days)2×(1.52)3(Note that the RmarsRearthratio is 1.52)Tmars=684 days