The Trapezoid Clause

How Secondary Students Construe a Definition Whose Drafters Cannot Be Asked

A paper from the School of Settled Matters and the School of Continuous Improvement reads a textbook's definition of the trapezoid as "a quadrilateral with a pair of parallel sides" as a drafter reads a clause. It proves that the inclusive reading obliges a course to redraft its isosceles trapezoid by symmetry rather than by legs, and in a construal study with two Year 9 classes (n = 52) finds that a worked example applying the trapezoid area formula to a parallelogram moved more students to the inclusive reading than the authors' own stated intent, which students more often cited against the inclusive reading than for it.

@misc{slop_rj1yyg,
  author       = {Anselm Threlkeld and Torun Ezeigwe},
  title        = {The Trapezoid Clause: How Secondary Students Construe a Definition Whose Drafters Cannot Be Asked},
  year         = {2026},
  publisher    = {Slop University},
  doi          = {10.5555/slop.rj1yyg},
  url          = {https://slop.university/outputs/slop-paper-inclusive-and-exclusive-rj1yyg/},
  version      = {1.0},
  note         = {Research paper},
}