Welcome to the forum!
You could use Trace Bitmap to create exactly that outer edge, and then just delete everything else. Let me know if you need specific instructions for deleting things. You don't need to draw a square first. Just import that image, open Path menu > Trace Bitmap, and probably just clicking Brightness Cutoff with default values should work ok.
Or if you want to draw it, here's what I would do.
- enable the Ellipse/Circle tool
- hold Ctrl while you drag the mouse (Ctrl makes it a perfect circle)
- Path menu > Object to Path
- duplicate it (Edit menu or this button
or the key shortcut)
- hold Ctrl and Shift while you drag one of the corner arrows (this enlarges the circle, and begins to create the outer shape that you want) (Ctrl makes sure it stays a circle, and Shift makes sure it enlarges from the center)
- switch to the Node tool
- Ctrl + a (this selects all the nodes for the new path)
- click this button (Add a node)
2 or 3 times (this adds several new nodes between the selected ones)
- deselect everything (click on open area of canvas)
- select a single node and drag it outwards slightly (notice when you select a node that you can see 2 straight lines with tiny circles on the end - those are the node handles - besides dragging the nodes, you can drag the handles to adjust the curves as you like - if you want more pointy corners, you can change the nodes from smooth to corner nodes, using this button on the Node tool control bar
) (if you're using an older version of Inkscape, some of your nodes might already be corner nodes)
After you have the outer shape like you what, select it and the other circle, then do Path menu > Combine. Then you'll be able to fill with black (or whatever).
