A 80-80-20 Triangle

shirali, shailesh (2016) A 80-80-20 Triangle. At Right Angles, 5 (2). pp. 63-65.

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Abstract

In the previous issue of At Right Angles, we studied a geometrical problem concerning the triangle with angles of 130 ◦ , 20 ◦ and 30 ◦ . We made the comment that the problem belongs to a class of geometrical problems dealing with triangles with numerous lines drawn within them, intersecting at angles whose measures are an integer number of degrees; we are required to find the measure of some indicated angle. In this note, we study another problem of this genre—a particularly famous such problem. We present a trigonometric solution as well as a ‘pure geometry’ solution.

Item Type:	Articles in APF Magazines
Uncontrolled Keywords:	Integer degree, sine rule, addition formula for sine, difference formula for cosine, isosceles, equilateral, triangle
Subjects:	Natural Sciences > Mathematics
Divisions:	Azim Premji University > University publications > At Right Angles
Depositing User:	Mr. Sachin Tirlapur
Date Deposited:	24 Sep 2018 11:42
Last Modified:	24 Sep 2018 11:42
URI:	http://publications.azimpremjifoundation.org/id/eprint/1440
Publisher URL:	http://apfstatic.s3.ap-south-1.amazonaws.com/s3fs-...

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