Protractor muscle | Article about protractor muscle by The Free Dictionary
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1. an instrument for measuring or drawing angles on paper, usually a flat semicircular transparent plastic sheet graduated in degrees
2. a surgical instrument for removing a bullet from the body
an instrument used to construct and measure angles in sketches and on charts. A protractor consists of a straightedge and a semicircle that is graduated in degrees from 0° to 180°. The precision of a protractor increases as its size becomes larger: the larger the semicircle, the smaller the value of a division. Protractors for very precise construction and measurement of angles—for example, in navigation—are equipped with a transparent straightedge and a goniometric vernier that rotates about the midpoint of the diameter of the semicircle.
A semicircular instrument used to construct and measure angles formed by intersecting lines of a plane; the midpoint of the diameter of the semicircle is marked and serves as the vertex of angles constructed or measured.
An instrument graduated in angular degrees for measuring or laying out angles.
A navigational instrument for measuring angles (headings, tracks, and bearings) on a map or a chart.