| 摘要 |
A set square is distinguished with respect to the conventional set squares in that there is rotatably mounted, on a broad side of the set square, a flat, semicircular body which, in the initial position, terminates flush, by means of a rectilinear edge serving as drawing edge, with a drawing edge of the set square, and in that there are arranged, on a broad side of the set square or of the rotatable body, two angular-degree graduations which are arranged at a distance one behind the other, of which one begins on the left-hand side, and the other on the right-hand side, with 0@ and which form a protractor in conjunction with the drawing edge of the rotatable body and the drawing edge of the set square.
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