How to find how far each planet is from the sun at a given day?

[deleted-834588]

Hi

I have an assignment that requires me to find the distance between each planet and the sun at any given days of it's orbital period. So for example I have to find out how far the Earth and Saturn are from the Sun on day 180 in the planet's orbital period. I have the values of mass, radius, semi-major axis,eccentricity and orbital period of the planets.

I just can't get the calculations to add up, I know that the Earth moves at a speed of approximately 30km/s, and that the Earth starts at a distance of 147054707km away from the Sun at its' closest and goes to 152140937km at its' furthest. By that logic I did 147054707 + (30 x 86400 x 365.25), since it's 30km per second X 86400 seconds in a day X 365.25 since it's the orbital period of Earth, and got an answer of 1094729435 which is waaaay off.

When I try to calculate it based on min and max value: (152140937 - 147054707) / 365.25 / 86400 = 0,161172903, which means that it actually moves 0,161172903km per second, and not 30km/s.
I just can't find the logic in calculating the different distances by the days in the Planet's orbital period.

Any help is greately appreciated!

[deleted-718508]

This forum is to help students with science fair projects. There are other, more appropriate forums for homework help. Good luck!