CN204537556U - A kind of central angle character demonstration teaching aid - Google Patents
A kind of central angle character demonstration teaching aid Download PDFInfo
- Publication number
- CN204537556U CN204537556U CN201520264788.7U CN201520264788U CN204537556U CN 204537556 U CN204537556 U CN 204537556U CN 201520264788 U CN201520264788 U CN 201520264788U CN 204537556 U CN204537556 U CN 204537556U
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- rotary ruler
- circle
- axle
- rotary
- ruler
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- Expired - Fee Related
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- Drawing Aids And Blackboards (AREA)
- Length-Measuring Instruments Using Mechanical Means (AREA)
Abstract
A kind of central angle character demonstration teaching aid, comprise the circle with circumferential lengths scale be arranged on substrate, the inside of circle is lower than outside, the position that substrate is positioned at the round center of circle is provided with axle, on axle, cover has length to be equal to the first rotary ruler of radius of circle, second rotary ruler, 3rd rotary ruler and the 4th rotary ruler, wherein, the first shrinkage-rule is connected with between the end of the first rotary ruler and the end of the 4th rotary ruler, the second shrinkage-rule is connected with between the end of the second rotary ruler and the end of the 3rd rotary ruler, centered by axle, substrate is provided with a circle angle index, the utility model can to " with circle or wait justify in, the arc that equal central angle is right is equal, right string equal, the distance from the chord to the centre of right string equal " theorem carry out demonstration and verification, deepen student to understand, improve their degree of awareness to this theorem.
Description
Technical field
The utility model belongs to field, particularly a kind of central angle character demonstration teaching aid.
Background technology
" with circle or wait justify in; the arc that equal central angle is right is equal; right string is equal; the distance from the chord to the centre of right string is equal ", being the Important Theorems in middle school mathematics, in the teaching of reality, is all generally that requirement student memorize mechanicallys this theorem, there is no the presentation tool responded, the understanding of student can not be deepened.
Summary of the invention
In order to overcome the shortcoming of above-mentioned prior art, the purpose of this utility model is to provide a kind of central angle character demonstration teaching aid, to carry out demonstration and verification to above-mentioned theorem.
To achieve these goals, the technical solution adopted in the utility model is:
A kind of central angle character demonstration teaching aid, comprise the circle 5 with circumferential lengths scale be arranged on substrate, the inside of circle 5 is lower than outside, the position that substrate is positioned at the center of circle of circle 5 is provided with axle 8, on axle 8, cover has length to be equal to the first rotary ruler 1 of circle 5 radiuses, second rotary ruler 2, 3rd rotary ruler 3 and the 4th rotary ruler 4, wherein, the first shrinkage-rule 7 is connected with between the end of the first rotary ruler 1 and the end of the 4th rotary ruler 4, the second shrinkage-rule 6 is connected with between the end of the second rotary ruler 2 and the end of the 3rd rotary ruler 3, centered by axle 8, substrate is provided with a circle angle index.
Described first rotary ruler 1, second rotary ruler 2, the 3rd rotary ruler 3 and the 4th rotary ruler 4 are transparent configuration.
One end of described first rotary ruler 1 is provided with the cover vertical with its length direction, is enclosed within axle 8 and rotates around axle 8; One end of second rotary ruler 2 is provided with the cover vertical with its length direction, is enclosed within axle 8 and rotates around axle 8; One end of 3rd rotary ruler 3 is provided with the cover vertical with its length direction, is enclosed within axle 8 and rotates around axle 8; One end of 4th rotary ruler 4 is provided with the cover vertical with its length direction, is enclosed within axle 8 and rotates around axle 8.
Compared with prior art, the utility model can to " with circle or wait circle in, the arc that equal central angle is right is equal; right string is equal; the distance from the chord to the centre of right string is equal " theorem carry out demonstration and verification, deepen student understanding, improve their degree of awareness to this theorem.
Accompanying drawing explanation
Fig. 1 is the utility model structural representation.
Embodiment
Embodiment of the present utility model is described in detail below in conjunction with drawings and Examples.
As shown in Figure 1, a kind of central angle character demonstration teaching aid, comprise the circle 5 with circumferential lengths scale be arranged on substrate, justify the inside of 5 lower than outside, the first rotary ruler 1, second rotary ruler 2, the 3rd rotary ruler 3 and the 4th rotary ruler 4 are transparent configuration and length is equal to the radius justifying 5.The position that substrate is positioned at the center of circle of circle 5 is provided with axle 8, is provided with the cover vertical with its length direction, is enclosed within axle 8 and rotates around axle 8 at the first rotary ruler 1, second rotary ruler 2, the 3rd rotary ruler 3 with one end of the 4th rotary ruler 4.Be connected with between the another end of the first rotary ruler 1 and the another end of the 4th rotary ruler 4 between the another end of the first shrinkage-rule 7, second rotary ruler 2 and the another end of the 3rd rotary ruler 3 and be connected with the second shrinkage-rule 6, centered by axle 8, substrate is provided with a circle angle index.
According to this structure, because the first rotary ruler 1, second rotary ruler 2, the 3rd rotary ruler 3 and the 4th rotary ruler 4 intersect at the home position of circle 5, and length is equal to the radius of circle 5, so the first shrinkage-rule 7 and the second shrinkage-rule 6 are the string of circle 5.First shrinkage-rule 7 is right strings of central angle of the first rotary ruler 1 and the 4th rotary ruler 4 composition, and the second shrinkage-rule 6 is the right strings of the central angle of the secondth rotary ruler 2 and the 3rd rotary ruler 3 composition.Rotate four rotary rulers, make above-mentioned two central angles equal, now can find that the length of standard on the first shrinkage-rule 7 and the second shrinkage-rule 6 is equal, and corresponding circular arc length is also equal, just demonstrates above-mentioned theorem thus.
Claims (3)
1. a central angle character demonstration teaching aid, it is characterized in that, comprise the circle with circumferential lengths scale (5) be arranged on substrate, the inside of circle (5) is lower than outside, the position that substrate is positioned at the center of circle of circle (5) is provided with axle (8), the upper cover of axle (8) has length to be equal to first rotary ruler (1) of circle (5) radius, second rotary ruler (2), 3rd rotary ruler (3) and the 4th rotary ruler (4), wherein, the first shrinkage-rule (7) is connected with between the end of the first rotary ruler (1) and the end of the 4th rotary ruler (4), the second shrinkage-rule (6) is connected with between the end of the second rotary ruler (2) and the end of the 3rd rotary ruler (3), centered by axle (8), substrate is provided with a circle angle index.
2. central angle character demonstration teaching aid according to claim 1, it is characterized in that, described first rotary ruler (1), the second rotary ruler (2), the 3rd rotary ruler (3) and the 4th rotary ruler (4) are transparent configuration.
3. central angle character demonstration teaching aid according to claim 1, is characterized in that, one end of described first rotary ruler (1) is provided with the cover vertical with its length direction, is enclosed within axle (8) and rotates around axle (8); One end of second rotary ruler (2) is provided with the cover vertical with its length direction, is enclosed within axle (8) and rotates around axle (8); One end of 3rd rotary ruler (3) is provided with the cover vertical with its length direction, is enclosed within axle (8) and rotates around axle (8); One end of 4th rotary ruler (4) is provided with the cover vertical with its length direction, is enclosed within axle (8) and rotates around axle (8).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520264788.7U CN204537556U (en) | 2015-04-28 | 2015-04-28 | A kind of central angle character demonstration teaching aid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520264788.7U CN204537556U (en) | 2015-04-28 | 2015-04-28 | A kind of central angle character demonstration teaching aid |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204537556U true CN204537556U (en) | 2015-08-05 |
Family
ID=53751528
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201520264788.7U Expired - Fee Related CN204537556U (en) | 2015-04-28 | 2015-04-28 | A kind of central angle character demonstration teaching aid |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN204537556U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107393377A (en) * | 2017-07-28 | 2017-11-24 | 孟海华 | A kind of electroscope formula teaching aid for being used to solve oval problem of values determination |
-
2015
- 2015-04-28 CN CN201520264788.7U patent/CN204537556U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107393377A (en) * | 2017-07-28 | 2017-11-24 | 孟海华 | A kind of electroscope formula teaching aid for being used to solve oval problem of values determination |
| CN107393377B (en) * | 2017-07-28 | 2019-05-21 | 孟海华 | It is a kind of for solving the electroscope formula teaching aid of oval problem of values determination |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20150805 Termination date: 20160428 |