what is geogebra

I have a copy of GeoGebra that I downloaded completely for free.  

I do my co-ordinate geometry graphing on Desmos

but

I draw all my euclidean geometry diagrams using GeoGebra.   It is well worth learning.

Geogebra is a piece of software that is commonly used to help students manipulate visual geometry problems.  You should be able to find a free trial online.

Here's the GeoGebra website:  http://www.geogebra.org/cms/en/

Here's another graphing site I like.....Desmos Grapher....easy to use.........https://www.desmos.com/calculator

(Nothing to download with Desmos!!!)