Purwanto
There are two definitions of trapezoid. One says that a trapezoid is a quadrilateral with exactly one pair of opposite parallel sides, and the other says that a trapezoid is a quadrilateral with at least one pair of opposite parallel sides. The difference is that the first uses the word "exactly" and the second uses the word "at least". These two definitions have some different consequences. We discuss some consequences of the definitions in some problems and solutions. © 2019 Published under licence by IOP Publishing Ltd.
Department of Mathematics, Universitas Negeri Malang, Jl. Semarang 5, Malang, 65145, Indonesia
