Van Aubel's Theorem: 11328 [2007, 925].
Am. Math. Mon., 2009
From Quadrilateral to Trapezoid: 11317 [2007, 745].
Am. Math. Mon., 2009
Perimeter by Integral: 11256.
Am. Math. Mon., 2008
A Permanent Lower Bound: 11253.
Am. Math. Mon., 2008
If AB Preserves A, then BA Preserves B: 11239.
Am. Math. Mon., 2008
Finding the Greatest Lower Bound: 11217.
Am. Math. Mon., 2007
Counting Lattice Quadrilaterals Tangent to an Ellipse: 11163.
Am. Math. Mon., 2007
Simple Roots for Polynomials: 11094.
Am. Math. Mon., 2006
Morley's Triangle and Lemma: 11038.
Am. Math. Mon., 2005
A Combinatorial Sum Goes on Tangent: 11044.
Am. Math. Mon., 2005
A Root Inequality: 10944.
Am. Math. Mon., 2003
A Differential Equation with Many Solutions: 10747.
Am. Math. Mon., 2000