What's "Geodreieck" in English? "Set square" seems to be more general?
I mean a ruler that's an isosceles triangle but not equilateral, having one corner 90° and the other two 45° each.
There's a ruler on the long side with 0 in the middle, a prominent line from that point to the opposite corner, so you can align a drawn line with it and use the ruler edge to draw another at a 90° angle to it, and there's angular dimensions marked on the other two edges, and in a half circle inside the triangle
@Anke wikipedia says these are universal in German school, which they definitely are not here in the US which might account for some of the vagueness you’re getting re:names
However it also claims that we either use “protractor triangle” or loan in Geodreieck, which seems reasonable consdiering English’s usual proclivity for borrowing words from everyone
@Satsuma Next you'll tell me you didn't have to buy the Dtandardised Box Of Twelve Colours Of Opaque Watercolours... ;)