Draw a square on double drafted face

[ross.kriel13]

Not sure if it is my Fuison360 knowledge that fails me here or my understanding of geometry. 

I created  a rectangle. Extruded it.  I created two drafts so that the front right corner is the lowest and back left is the highest. 

Now I need to be able to draw a square on it as I need to align other items in my sketch to  the square but if draw a square, even on an offset plane it never seems to line up. 

How do I go about aligning my sketch to a face that has been doubled drafted? 

Edit: Included a sample, watered down file for the question.

[TheCADWhisperer]

Are there any unresolved issues highlighted in your Timeline?

Can you File>Export your *.f3d file to your local drive and then Attach it here to a Reply?

[ross.kriel13]

I've edited the  question to include a sample file. Even with a basic design I seem to get the same issue.

[ross.kriel13]

I've edited the question to include a sample file. Even with a basic design I seem to get the same issue

[TheCADWhisperer]

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@ross.kriel13 wrote:

.... that fails me here or my understanding of geometry. 

Now I need to be able to draw a square on it as I need to align other items in my sketch to  the square but if draw a square

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You keep writing "square", but I think you mean rectangle.

In any case - the planar edges on that face are not at 90° to each other.