• Journal for History of Mathematics
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• v.33 no.3
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• pp.155-165
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• 2020

Pythagorean theorem is a proposition on the relationship between the lengths of three sides of a right triangle. It is well known that Pythagorean theorem for Euclidean geometry deforms into an interesting form in non-Euclidean geometry. In this paper, we investigate a new perspective that replaces right triangles with 'proper triangles' so that Pythagorean theorem extends to non-Euclidean geometries without any modification. This is seen from the perspective that a rectangle is an equiangular quadrilateral, and a right triangle is a half of a rectangle. Surprisingly, a proper triangle (defined by Paolo Maraner), which is a half of an equiangular quadrilateral, satisfies Pythagorean theorem in many geometries, including hyperbolic geometry and spherical geometry.

• Communications of Mathematical Education
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• v.20 no.3 s.27
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• pp.469-482
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• 2006

It ill give much interest both to the teacher and student that paper crane makes interesting mathematical investment possible. It is really possible for the middle school students to invest mathematical activity such as the things about triangle and square, resemblance, Pythagorean theorem. I reserched how this mathematical investment possible through folding and unfolding paper crane and analyzed the mathematical meaning.

• Journal for History of Mathematics
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• v.32 no.5
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• pp.241-255
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• 2019

The proposition that the parallel axiom and the Pythagorean theorem are equivalent in the Hilbert geometry is true when the Archimedean axiom is assumed. In this article, we examine some specific plane geometries to see the existence of the non-archimidean Hilbert geometry in which the Pythagorean theorem holds but the parallel axiom does not. Furthermore we observe that the Pythagorean theorem is equivalent to the fact that the Hilbert geometry is actually a semi-Euclidean geometry.

• Communications of Mathematical Education
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• v.18 no.2 s.19
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• pp.251-263
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• 2004

피타고라스 정리와 코사인 제 2법칙 사이에는 어떤 관계가 있을까. 현재 우리의 교육과정에서는 피타고라스 정리는 중학교 3학년에서 코사인 제 2법칙은 고등학교 1학년에서 배운다. 그런데, 이 두 가지 수학적 사실 사이에는 밀접한 관계가 있다. 피타고라스 정리의 확장으로서 코사인 제 2법칙을 유도할 수 있다는 것이다. 코사인 제2법칙이 소개되어진 최초의 문헌은 Euclid의 <원론>으로 거슬러 올라간다. <원론>에 소개되어진 코사인 제 2법칙의 증명방법으로 시작하여 수 천년 동안 증명되어온 다양한 증명방법을 소개하고자 한다. 특히, 직각삼각형과 원이라는 큰 틀을 바탕으로 코사인 제 2법칙의 증명 방법에 대해 고찰하고, 그 외 다양한 증명방법을 분석하고자 한다.

• Journal for History of Mathematics
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• v.34 no.6
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• pp.205-223
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• 2021

It has been argued that as for the origin of the Pythagorean theorem, the theorem had already been discovered and proved before Pythagoras, and the historical records of ancient mathematics have confirmed various uses of this theorem. The purpose of this study is to examine the relevance of its name caused by Eurocentrism and the weakness of its use in Korean school mathematics and to seek improvements from a critical point of view. To this end, the Pythagorean theorem was reviewed from the perspectives of the history of mathematics and mathematics education. In addition, its name in relation to objective mathematical contents regardless of any specific civilization and its use as a starting point for teaching the theorem in school mathematics were suggested.

• Journal of the Korean Data and Information Science Society
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• v.25 no.3
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• pp.493-499
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• 2014

The Pythagorean won-loss formula postulated by James (1980) indicates the percentage of games as a function of runs scored and runs allowed. Several hundred articles have explored variations which improve RMSE by original formula and their fit to empirical data. This paper considers a variation on the formula which allows for variation of the Pythagorean exponent. We provide the most suitable optimal exponent in the Pythagorean method. We compare it with other methods, such as the Pythagenport by Davenport and Woolner, and the Pythagenpat by Smyth and Patriot. Finally, our results suggest that proposed method is superior to other tractable alternatives under criterion of RMSE.

• East Asian mathematical journal
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• v.28 no.4
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• pp.419-433
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• 2012

In this paper, by using the inductive method, recurrence relation, the unit circle, circle to inscribe a right-angled triangle, formula of multiple angles, solution of quadratic equation and Fibonacci numbers, we study various problem solving methods to find pythagorean triple.

• The Monthly Technology and Standards
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• s.79
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• pp.86-89
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• 2008

• East Asian mathematical journal
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• v.31 no.4
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• pp.459-481
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• 2015

In this study, we investigated whether the theorem is established even if we replace a 'square' element in the Euclidean proof of the Pythagorean theorem with different figures. At this time, we used different figures as equilateral, isosceles triangle, (mutant) a right triangle, a rectangle, a parallelogram, and any similar figures. Pythagorean theorem implies a relationship between the three sides of a right triangle. However, the procedure of Euclidean proof is discussed in relation between the areas of the square, which each edge is the length of each side of a right triangle. In this study, according to the attached figures, we found that the Pythagorean theorem appears in the following three cases, that is, the relationship between the sides, the relationship between the areas, and one case that do not appear in the previous two cases directly. In addition, we recognized the efficiency of Euclidean proof attached the square. This proving activity requires a mathematical process, and a generalization of this process is a good material that can experience the diversity and rigor at the same time.

• Journal of the Korean School Mathematics Society
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• v.23 no.3
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• pp.277-297
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• 2020

The purpose of this study is to understand how the shift of the Pythagorean theorem influenced the representation of irrational numbers in the 3rd grade textbook of 2015 revised mathematics curriculum by textbook analysis. Specifically, the changes in the representation of irrational numbers were examined in two aspects based on the nature of irrational numbers and the teaching and learning methods of the 2015 revised mathematics curriculum. First, we analyzed the learning opportunities related to the existence of irrational numbers that were potentially provided by treating irrational numbers as geometric representations in textbooks, and confirmed that Pythagorean theorem was used. Next, we analyzed opportunities to recognize the necessity of irrational numbers provided by numerical representations of irrational numbers. This study has significance in that it confirmed the possibility and limitation of learning opportunities related to the existence and necessity of irrational numbers that were potentially provided by changes in irrational number representations in the 2015 revised textbooks.