Arc length that parallel chords pressed from both sides equals theorem demonstration teaching aid

The utility model provides an arc length that parallel chords pressed from both sides equals theorem demonstration teaching aid, the circle that have circumference length scale of setting on the base plate, the centre of a circle position of circle is provided with the pivot, the one end of pivot is connected on the base plate, the mid point in the one side of ruler is connected to the end in addition, the another side of ruler is provided with the spout along its length direction, the diameter of the length more than or equal to circle of ruler, an extension rule's bottom surface is fixed with first gleitbretter, the 2nd extension rule's bottom surface is fixed with the second gleitbretter, first gleitbretter is arranged in the spout, and just an extension rule is perpendicular with the ruler, the second gleitbretter is arranged in the spout, and just the 2nd extension rule is perpendicular with the ruler, first gleitbretter drives an extension rule and slides along ruler length direction in the spout, the second gleitbretter drives the 2nd extension rule and slides along ruler length direction in the spout, the utility model discloses can demonstrate the verification to the theorem of " two arcs that the parallel chords pressed from both sides of circle equal ", deepen the student and understand, improve their degree of awareness to this theorem.