Clark Kimberling (born November 7, 1942 in

Hinsdale, Illinois Hinsdale is a village in Cook and DuPage counties in the U.S. state of Illinois. Hinsdale is a western suburb of Chicago. The population was 17,395 at the 2020 census, most of whom lived in DuPage County. The town's ZIP code is 60521. The town ...

) is a mathematician, musician, and composer. He has been a mathematics professor since 1970 at the

University of Evansville The University of Evansville (UE) is a private university in Evansville, Indiana. It was founded in 1854 as Moores Hill College. The university operates a satellite center, Harlaxton College, in Grantham, England. UE offers more than 80 differ ...

. His research interests include

triangle center In geometry, a triangle center (or triangle centre) is a point in the plane that is in some sense a center of a triangle akin to the centers of squares and circles, that is, a point that is in the middle of the figure by some measure. For example ...

integer sequence In mathematics, an integer sequence is a sequence (i.e., an ordered list) of integers. An integer sequence may be specified ''explicitly'' by giving a formula for its ''n''th term, or ''implicitly'' by giving a relationship between its terms. For ...

s, and

hymnology Hymnology (from Greek ὕμνος ''hymnos'', "song of praise" and -λογία ''-logia'', "study of") is the scholarly study of religious song, or the hymn, in its many aspects, with particular focus on choral and congregational song. It may be m ...

. Kimberling received his PhD in mathematics in 1970 from the

Illinois Institute of Technology Illinois Institute of Technology (IIT) is a private research university in Chicago, Illinois. Tracing its history to 1890, the present name was adopted upon the merger of the Armour Institute and Lewis Institute in 1940. The university has prog ...

, under the supervision of

Abe Sklar Abe Sklar (November 25, 1925 – October 30, 2020) was an American mathematician and a professor of applied mathematics at the Illinois Institute of Technology (IIT) and the inventor of copulas in probability theory. Education and career Sklar ...

. Since at least 1994, he has maintained a list of triangle centers and their properties. In its current on-line form, the

Encyclopedia of Triangle Centers The Encyclopedia of Triangle Centers (ETC) is an online list of thousands of points or "centers" associated with the geometry of a triangle. It is maintained by Clark Kimberling, Professor of Mathematics at the University of Evansville. , the l ...

, this list comprises tens of thousands of entries. He has contributed to ''The Hymn'', the journal of the

Hymn Society in the United States and Canada The Hymn Society in the United States and Canada – founded in 1922 as The Hymn Society of America and renamed in 1991 – is a not-for-profit organization for those people who: * believe that congregational song is an integral component of worsh ...

; and in the '' Canterbury Dictionary of Hymnology''.

Kimberling's golden triangle

Robert C. Schoen has defined a "golden triangle" as a triangle with two of its sides in the

golden ratio In mathematics, two quantities are in the golden ratio if their ratio is the same as the ratio of their sum to the larger of the two quantities. Expressed algebraically, for quantities a and b with a > b > 0, where the Greek letter phi ( ...

. Kimberling has proposed that Schoen's definition of golden triangle be extended to include triangles which have angles that are in the golden ratio. Kimberling has described a "doubly golden triangle" which has two sides that are in golden ratio and which also has two angles that are in golden ratio.Clark Kimberling
"Two Kinds of Golden Triangles, Generalized to Match Continued Fractions"
''Journal for Geometry and Graphics'', Volume 11 (2007), No. 2, pp. 165–171.

References

External links

Kimberling's home page at UE

* Living people 1942 births 20th-century American mathematicians 21st-century American mathematicians Geometers Hymnologists Illinois Institute of Technology alumni Number theorists Musicians from Evansville, Indiana People from Hinsdale, Illinois American recorder players University of Evansville faculty Mathematicians from Illinois {{US-mathematician-stub