Final answer:
The length of a year on Mars is 687.364 days.
Step-by-step explanation:
A year on Mars is 1.88 times as long as a year on Earth, which is 365.3 days. To find the length of a year on Mars, we can multiply the length of an Earth year by the ratio. So, the length of a year on Mars is 365.3 x 1.88 = 687.364 days.