| 摘要 |
A combined ruler protractor (13) which allows easy drawing of inclined lines and/or measuring angles using a transparent scale. The starting point of very inclined line of the protractor coincides with the starting point of a scale line of the linear scale (12, 12') on the edge (11, 11') of the ruler (13). The scale lines of the protractor are setting steps of one degree, growing from 0 to 90 degrees; every 10-degree-line (1, 2, 3, 3', 4, 5, 6, 7, 8, 9) being specially marked. |
