Neptune takes the longest to revolve around the sun.
Mars takes the longest of the inner planets.
If you still consider Pluto a planet, than Pluto takes the longest time to move around the sun. If not, Neptune takes the longest amount of time.
Uranus
This would depend on the planet, earth takes a year to go round the sun but that is because we named the time it takes for us to go round the sun a "year". The closer to the sun a planet is the less time it takes to circle it.
IN our solar system, the planet Neptune takes the longest. Or, if you want to include Pluto, Pluto. Or, if you want to include ALL of the "dwarf planets", then Eris (a.k.a. "Xena") takes the longest.
Neptune does and it takes 164.8 years to do so.
Mars takes the longest of the inner planets.
Neptune takes the longest as it is the farthest away.
If you still consider Pluto a planet, than Pluto takes the longest time to move around the sun. If not, Neptune takes the longest amount of time.
Mercury - its the closest to sun so takes it less for one complete revolution
Pluto
Technically, since Pluto is no longer a planet, but a dwarf planet, Uranus is the planet that takes the longest to orbit the sun.
Uranus
As it's the furthest planet out, Neptune takes the longest to orbit our sun, taking some 165 years to do so.
pluto has the longest year it takes 248 earth years in one revalution
Approxiamtely 6756313285.666678487m
Neptune.