| 摘要 |
An angle measuring device for use in preparing construction layouts, which includes: a generally flat outer circular plate, a generally flat inner circular plate, a first pair of string connectors, a second pair of string connectors, and a means for positioning the angle measuring device over a selected point. The outer and inner circular plates share a common plane. The outer circular plate defines an outer circumference, an inner circumference, and a circular interior aperture. The inner circumference is marked up with indicia for measuring angles. The inner circular plate rotates freely inside the inner circumference and about the center-hole.
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