RT Journal Article
SR Electronic(1)
A1 Man, Yiu-Kwong
YR 2019
T1 An elementary proof of Ptolemy’s theorem
JF Learning and Teaching Mathematics,
VO 2019
IS 27
SP 23
OP 25
PB Association for Mathematics Education of South Africa (AMESA),
SN 1990-6811,
AB IntroductionPtolemy’s theorem is a well-known result in plane geometry and can be stated as follows:*If ABCD is a cyclic quadrilateral with sides a, b, c, d and diagonals e, f, then ac +bd = ef*In this article we present an elementary proof of Ptolemy’s theorem based on basic trigonometry, circle geometry and transformation geometry. The proof is different to those described elsewhere – see for example Johnson (1929), Coxeter & Greitzer (1967), Ostermann & Wanner (2012) and Miculita (2017).,
LA English,
UL https://journals.co.za/content/journal/10520/EJC-19eb008a40