Apps for making geometric shapes (math) Is there any apps for making geometric shapes (math)? I need to make shapes like rhombus and equilateral triangles. 

I have already posted this in the math forum, but I think this is more related to apple.
Grapher.app

You might want to take a look at /Application/Utilities/Grapher.app. It is a graphical calculator that can create 2D and 3D shapes.

x2y2z2=42



Here is a starters tutorial that looks fine: http://computers.tutsplus.com/tutorials/getting-started-with-grapher-your-macs-built-in-graph-tool--mac-48440