CSS scale height to match width - possibly with a formfactor

Question

I have implemented a GoogleMapsV3 map in a twitterBootstrap basic responsive design site.

But my question is quite simple: i have:

Answer 1

I need to do "fluid" rectangles not squares.... so THANKS to JOPL .... didn't take but a minute....

#map_container {
     position: relative;
     width: 100%;
     padding-bottom: 75%;
}


#map {
    position:absolute;
    width:100%;
    height:100%;
}