| 摘要 |
<p>The invention relates to a device which enables two or more measuring systems to be combined on a circular support base. The invention further relates to a device for measuring or marking an angular sector in degrees, in 'percent' of a circular diagram, in 'percent' of a semi-circular diagram and for measuring or marking a segment. The device consists of a circular base (1) which has a circular hole in the center (2) and which is graduated in degrees on the periphery, from 0 to 360; a center (2) circle (3), which is graduated in 'percent', from 0 to 100, and a recess (4). The semi-discs (21) of the centers (22) and (23) are removed from the circle (3), the semi-circular edge (24) is graduated in 'percent', the semi-circular edge (25) is graduated in degrees and the rectilinear edges of the semi-discs (21) are in millimeters. The device according to the invention is particularly useful for pupils and teachers.</p> |
