For this first half, I referenced Heathenx’s tutorial. I will include the video tutorial at the end of the post.
1. Create a circle in Inkscape (no fill, just a line stroke)
2. On top of the circle, create a square (fill and stroke, but not mandatory).
3. Place the square over the bottom half of the circle (the square will be totally covering the bottom half of the circle).
4. Select both the circle and the square using the Shift key.
5. In the Path menu choose Path–>Cut Path
6. You’ll now have a separate arch (you can delete the other by products, unless you find something to use them for 🙂 )
7. Type your text
8. Select the arch you created and the text using the Shift key.
9. In the Text menu, select Text—> Put on Path
10. You can adjust the path points on the arch (using the Edit Path Nodes tool), which will change the arch position of your text.
11. Select the arch and in the Fill and Stroke dialog, set the arch’s Alpha channel to zero (0). This will make the arch invisible but the text will stay arched. Do not delete the arch or you’ll break the link b/w the arch and the text and the text will no longer arch (since you deleted the reference path for the text).
Here is the video tutorial by Heathenx: