Posted by Sam on .
Can You help me with this question?
The distance from the earth to the sun is about 1.5 X 10^8 km, while the distance from the earth to the moon is about 3.8 X 10^5 km. If a scale model of the solar system is constructed so that the distance from the Earth to the Sun is 100 meters, what will be the distance from the Earth to the Moon? Express your answer in meters.

Math 
Steve,
1.5*10^8/3.8*10^5 = 100/x
394 = 100/x
x = .253m 
Math 
Sam,
How did you get .253m? Wouldn't you multiply by 100?

Math 
Steve,
if 394 = 100/x, x = 100/394

Math 
Steve,
besides, if the sun is 100m away, would you not expect the moon to be a lot closer?

Math 
bobpursley,
an interesting variation of this, in which I have had students actually do this outside, is to determine the scale distance from Earth to Pluto. As I recall, and you can work it out, it is about 4000 meters, about 2.5 miles.

Math 
Steve,
There is a model of the solar system in Peoria, IL and nearby towns. Discover magazine did a nice article on it a while back.
discovermagazine.com/1995/mar/theplanetsofpeor482
If you're ever visiting there, give it a look. 
Math 
Sam,
Thank you! That helped.