How to make a rhombus-Thank you all for your suggestions. After sleeping on the issue i decided to make a 6 sided polygon. Turned on snapping and drew lines from one corner to the center and back to the opposite corner. This produces the desired shape

[mikemel (Michael Melvin)]

I want to make a rhombus (4 sides all equal in length) but not with 90 degree corners. I want a “star” shape with 2 120 degree angles and 60 degree angles.
Mike M

[fred_dot_u (fred ungewitter)]

There may be more than one way to accomplish your task, but consider to create two lines with either specified angle and with the appropriate lengths. Duplicate the two lines and rotate the copy, then join the ends using the node tool.

[thelmuth (Tim Helmuth)]

Make a square or rectangle with the sides you desire then place a vertical line near it. Select the line and rotate by 30 degrees. That will be your guide for skewing the rectangle with the skew tool. (the square that I highlighted in the screenshot)

[Marcus_Wakefield]

Something similar has been asked before and the simplest way that I can think of is in a post I made here: Rectangle to Parallelogram - #18 by Marcus_Wakefield

Hope this helps.

EDIT:
This method does have the potentially unwanted result that the side length is altered. If you want to keep the side length the same, then enter two scaling factors:
xscale = sqrt(2)*sin(angle/2)
yscale = sqrt(2)*cos(angle/2)

“sqrt(2)” is obviously constant so you can enter “1.4142” instead of “sqrt(2)”.

So, for example if you want a rhombus with a 60° corner angle then enter the following into the X scale: 100*1.4142*sin(60/2)
and the Y scale: 100*1.4142*cos(60/2)