What about Mondrian?
The belief in the goden ratio is that big that on the website that's pointing to the use of the golden ration in art is writing that Mondrian made use of it, but doesn't give any argument and not even shows any dimension.
"The painter Mondrian also made use of it" (dutch)
So we do it ourselves. In the applet below you can compare all rectangles with a green 'golden rectangle'.
You can drag or turn it, searching for a golden ratio somewhere...
Good luck!
What was the real aim of Mondrian?
You can give you students as a tast to draw something similar, colouring and knitting according to the golden ratio. It's fun, but it's missing completely the real aim of Mondriaan. A bettere start for more information on Mondriaan are som webpages:
Mondrian also writes himself on his thinking.
There's a dutch text online in the digitale bibliotheek voor de Nederlandse Letteren.
Here too you will search in vane for the golden ratio.