How to set up a to scale model of the distances between planets of the Solar System on a football field

I want to set up a model of the solar system having distances between the planets to scale. This will be on a football field 100 meters in length. So how do I make the distances between the planets to scale on a football field that's 100 meters. I was thinking ratios or proportions but I'm really not sure.

Sun is sitting in one goal, Pluto is 100 yards away. (we're still going to count pluto here :)

Now we look up Pluto and find that he's 3670052070 miles away. He's our constant.

Neptune is 2829691160

2829691160 / 3670052070 = .7710
Neptune is 77 meters away from the sun.

Uranus is 1783950480 / 3670052070 = .4861
Uranus is 48.6 meters from the sun.

etc.

You can google up and divide the rest yourself. At the bleachers begin the Oort Cloud, and it runs out past the parking lot. :)

Well, start by using the sun at one end of the field, and the farthest planet (Neptune) at the farthest distance (100 meters). That determines the scale for the rest of the planets.

Now look up the distance from the sun to Neptune. That is also called Neptune's "semi-major axis", and you can find on Wikipedia that it's about 4.5 billion kilometers. So your scale is:

100 meters : 4,500,000,000 km
Or, more simply:
1 meter : 45,000,000 km

So that means every meter in you model stands for 45 million kilometers of space.

Now look up the semi-major axis for all the other planets (in Wikipedia or elsewhere). And then use your scale to figure out how many meters that stands for in your model. The equation is:

Number of meters = (planet's semi-major axis) / 45,000,000 km

For example, Mercury's semi-major axis is 58,000,000 km. So its distance in the model would be 58,000,000/45,000,000 = 1.29 meters.

I have previously seem such models, go to National Geographic and key the scale models in sine the late 60's, & up,....& see what you find...have a **good friend in Engineering? "they'd be a wonderful help"!