CN201927239U - Teaching aid for demonstrating internal angles and external angles of triangle - Google Patents

Abstract

The utility model discloses a teaching aid for demonstrating internal angles and external angles of a triangle, which is suitable for mathematics classroom teaching in junior middle schools, and can enable students to visually see the change relation among three internal angles of the triangle and rapidly master the relation between the internal angles and the external angles. The teaching aid comprises an upper straight ruler, a left straight ruler, a right straight ruler, angle rulers, pin shafts, nuts, and the like, wherein, the upper straight ruler, the left straight ruler and the right straight ruler are all made of transparent plastic laths; connecting holes and indicating graduation lines are arranged at the two ends of each straight ruler; the angle rulers are made of transparent organic glass plates; and angle graduation lines are arranged on the circumferences of the angle rulers. The structure of the teaching aid is that the left end of the upper straight ruler is hinged with the upper end of the left straight ruler and the corresponding angle ruler; the right end of the upper straight ruler is hinged with the upper end of the right straight ruler and the corresponding angle ruler; and the lower end of the left straight ruler is hinged with the lower end of the right straight ruler and the corresponding angle ruler.

Description

A kind of teaching aid of demonstrating the angle sum of a triangle exterior angle

Technical field

The utility model belongs to a kind of middle school teaching apparatus, is applicable to the Junior Mathematics classroom instruction, is a kind of teaching aid of demonstrating the angle sum of a triangle exterior angle concretely.

Background technology

In the Junior Mathematics course, geometric triangulation is partly than being easier to carry out object teaching, but China's teaching aid in this respect also lacks very much at present, for example when talking about a leg-of-mutton exterior angle and equal two other non-conterminous interior angle sum, teacher will lean against and draw picture to go to explain on blackboard, otherwise be exactly to utilize how much method to prove that whole process is more loaded down with trivial details, the classmate also is not easy to understand.If a teaching aid intuitively can be arranged, that will can be very helpful to classmates' understanding and memory.

Summary of the invention

In order to overcome the deficiency of how much teaching aids of existing Junior Mathematics study course intermediate cam, the utility model provides a kind of teaching aid of demonstrating the angle sum of a triangle exterior angle, it helps to cultivate and excite the enthusiasm of classmates' learning mathematics class, can allow classmates see variation relation between the Atria interior angle intuitively, grasp the relation at interior angle and exterior angle rapidly.The demonstration teaching aid at this angle sum of a triangle exterior angle can make the blackboard formula teaching on plane become three-dimensional, intuitively, teaching in kind, this is useful to manipulative ability and the creativity that will improve classmates from now on.

To achieve these goals, the technical solution adopted in the utility model is: a kind of teaching aid of demonstrating the angle sum of a triangle exterior angle comprises ruler, left ruler, right ruler, bevel protractor, bearing pin, nut etc.Wherein go up ruler, left ruler, right ruler and make by the opaque plastics lath, all there are connecting hole and indication groove in its two ends; Bevel protractor is made by transparent poly (methyl methacrylate) plate, and the circumference place is provided with the angle groove; Structure of the present utility model is: upward the upper end and the bevel protractor of the left end of ruler and left ruler are hinged, and the right-hand member of last ruler and the upper end of right ruler and bevel protractor are hinged, and the lower end of left ruler and the lower end of right ruler and bevel protractor are hinged.

The beneficial effects of the utility model are: the relation between leg-of-mutton each angle that last ruler, left ruler, right ruler are constituted comes into plain view, three-dimensional directly perceived, by changing the variation that a leg-of-mutton interior angle promptly can be observed two other interior angle and exterior angle, help in classmates' brain, setting up one about leg-of-mutton mathematical model.

Using method of the present utility model is: the indication groove at three ruler two ends of adjustment aligns with the angle groove on the bevel protractor, read the reading at leg-of-mutton each three interior angles and two exterior angles and note, to go up ruler again maintains static, swing left ruler and right ruler, the reading at each interior angle of reading and recording and exterior angle once more, can suitably adjust the bevel protractor of below during reading of data, angle groove on it is alignd with indication groove on the ruler, at last two groups of numerals are compared, the inspiration classmates find rule wherein.

Description of drawings

Fig. 1 is an one-piece construction synoptic diagram of the present utility model;

Fig. 2 is the cut-open view among Fig. 1;

Among the figure, 1. go up ruler, 2. left ruler, 3. right ruler, 4. bevel protractor, 5. bearing pin, 6. pad, 7. nut, 8. indication groove.

Embodiment

Below in conjunction with accompanying drawing structure of the present utility model is further detailed: in the drawings, a kind of teaching aid of demonstrating the angle sum of a triangle exterior angle comprises ruler 1, left ruler 2, right ruler 3, bevel protractor 4, bearing pin 5, nut 7, pad 8.Wherein go up ruler 1, left ruler 2, right ruler 3 and make by the opaque plastics lath, all there are connecting hole and indication groove 8 in its two ends; Bevel protractor 4 is made by transparent poly (methyl methacrylate) plate, and the circumference place is provided with the angle groove; Structure of the present utility model is: upward the upper end and the bevel protractor 4 of the left end of ruler 1 and left ruler 2 are hinged and fastening by pad 6 nuts 7 through bearing pin 5, the upper end of the right-hand member of last ruler 1 and right ruler 3 and bevel protractor 4 are hinged and fastening by pad 6 nuts 7 through bearing pin 5, and the lower end of the lower end of left ruler 2 and right ruler 3 and bevel protractor 4 are hinged and fastening by pad 6 nuts 7 through bearing pin 5.

Claims (3)

1. teaching aid of demonstrating the angle sum of a triangle exterior angle, it is characterized in that: it comprises ruler, left ruler, right ruler, bevel protractor, wherein going up ruler, left ruler, right ruler makes by the opaque plastics lath, bevel protractor is made by transparent poly (methyl methacrylate) plate, structure of the present utility model is: upward the upper end and the bevel protractor of the left end of ruler and left ruler are hinged, the right-hand member of last ruler and the upper end of right ruler and bevel protractor are hinged, and the lower end of left ruler and the lower end of right ruler and bevel protractor are hinged.

2. a kind of teaching aid of demonstrating the angle sum of a triangle exterior angle according to claim 1 is characterized in that: upward ruler, left ruler, right ruler two ends are equipped with the indication groove.

3. a kind of teaching aid of demonstrating the angle sum of a triangle exterior angle according to claim 1 is characterized in that: there is the angle groove at the circumference place of bevel protractor.

Images