Trap a Surprise in an Isosceles Trapezoid
Margaret M. Housinger
	Isosceles trapezoids with integral sides in which a circle can be inscribed.
	(889, 1996)  12 - 14

Theorems in Motion: Using Dynamic Geometry to Gain Fresh Insights
Daniel P. Scher
	Construction of a constant-perimeter rectangle; a constant area rectangle.
	(889, 1996)  330 - 332

Concept Worksheet: An Important Tool for Learning
Charalampos Toumasis
	The example presented is geometric in nature, it deals with the characterization of a 
	parallelogram.
	(88, 1995)  98 - 100

When Is a Quadrilateral a Parallelogram?
Charalampos Toumasis
	Investigations of sets of sufficient conditions.
	(87, 1994)  208 - 211

Creative Teaching Will Produce Creative Students
Stephen Krulik and Jess A. Rudnick
	Solving the problem of finding all rectangles with integral dimensions whose area 
	and perimeter are numerically equal.
	(87, 1994)  415 - 418

Counting Embedded Figures
Timothy V. Craine
	Activities.  How many triangles, squares, rectangles, etc., are there in a given 
	figure?
	(87, 1994)  524 - 528, 538 - 541

A Quadrilateral Hierarchy to Facilitate Learning in Geometry
Timothy V. Craine and Rheta N. Rubenstein
	Creating a "family tree" for quadrilaterals to enable generalization 
	of results.  Analytic proofs are also involved.  
	(86,1993)  30 - 36

Ladders and Saws
Debra Tvrdik  and David Blum
	An activity for demonstrating many geometric relationships from 
	angle sums of polygons to properties of parallelograms.  
	(86, 1993)    510 - 513

Improving Students' Understanding of Geometric Definitions
Jim Hersberger and Gary Talsma
	Sharing Teaching Ideas.  Activities involving standard convex
	quadrilaterals.
	(84, 1991)  192 - 194

Area Ratios of Quadrilaterals
David R. Anderson and Michael J. Arcidiacono
	Looks at the area of the quadrilateral formed by joining points on
	the sides of a given quadrilateral.
	(82, 1989)   176 - 184

An Application of the Criteria ASASA for Quadrilaterals
Spencer P. Hurd
	A series of results leading to the Theorem of Pythagoras.
	(81, 1988)   124 - 126

Discoveries with Rectangles and Rectangular Solids
Lyle R. Smith
	Differentiating between area and perimeter for rectangles and between
	volume and surface area for rectangular solids.
	80, (1987)  274 - 276.

Geometrical Adventures in Functionland
Rina Hershkowitz, Abraham Arcavi, and Theodore Eisenberg
	Determining the change in area produced by making a change in some
	property of a particular figure.
	80, (1987)  346 - 352.

Median of a Trapezoid
Pamela Allison
	Using the result about the segment joining the midpoints of the sides
	of a triangle in order to find the length of the median of a trapezoid.
	79, (1986)  103 - 104.

A Postal Scale Linkage
Andrew A. Zucker
	A "Sharing Teaching Idea".  Use of physical models.  Application to
	quadrilaterals.
	78, (1985)  431 - 43

The Rhombus Construction Company
Joseph A. Troccolo
	Activities for looking at properties of a rhombus.
	76, (1983)  37 - 41.

Triangles, Rectangles, and Parallelograms
Melfried Olsen and Judith Olsen
	Activities involving the manipulation of models of geometric figures.
	76, (1983)  112 - 116.

President Garfield's Configuration
Allan Weiner
	Geometric and trigonometric results derived from the trapezoidal
	configuration used by Garfield in his proof of the theorem of
	Pythagoras.
	75, (1982)  567 - 570.

Spirolaterals
Richard Brannan and Scott McFadden
	Activities involving figures made up of rectangles on a grid.
	74, (1981)  279 - 282, 285.

Measuring Squares To Prepare For Pi
Don E. Ryote
	Seven activities leading to a consideration of the ratio of perimeter
	to diagonal for a rectangle.
	74, (1981)  375 - 379.

Properties Of Quadrilaterals
Stephen Maraldo
	Definitions, theorems, and a diagram.
	73, (1980)  38 - 39.

Area and Cost Per Unit: An Application
Jan J. Vandever
	Activities providing practice with area formulas.
	73, (1980)  281 - 284, 287.

Are Circumscribable Quadrilaterals Always Inscribable?
Joseph Shin
	A condition under which they will be is developed.
	73, (1980)  371 - 372.

Graphing - Perimeter - Area
Merrill H. Murphy
	Activities concerning areas and perimeters of polygons.  A coordinate
	system is used
	73, (1980)  441 - 444.

Computer Classification Of Triangles and Quadrilaterals -
A Challenging Application
J. Richard Dennis
	Computer application, uses coordinates of vertices.
	71, (1978)  452 - 458.

Exploring Skewsquares
Alten T. Olson
	Properties of quadrilaterals having congruent, mutually perpendicular
	diagonals.  (Transformational approach.)
	69, (1976)  570 - 573.

Consistent Classification Of Geometric Figures
Joe K. Smith
	Suggestions for developing classification systems.
	69, (1976)  574 - 576.

Midpoints and Quadrilaterals
W.J. Masalski
	Activities for considering what happens when figures are formed from
	polygons by using midpoints of segments.
	68, (1975)  37 - 44.

The Area Of A Parallelogram Is The Product Of Its Sides
William J. Lepowsky
	An experiment concerning the area of a parallelogram.
	67, (1974)  419 - 421.

An Absent-Minded Professor Builds A Kite
Norman Gore and Sidney Penner
	Can you build a trapezoid having the same side lengths as those
	of a kite?
	66, (1973)  184 - 185.

Midpoints and Measures
L. Carey Bolster
	Activities involving figures formed using midpoints of sides of
	triangles and quadrilaterals.
	66, (1973)  627 - 630.

Urquhart's Quadrilateral Theorem
Howard Grossman
	A proof and a generalization.
	66, (1973)  643 - 644.

Problem Solving In Geometry
Arthur A. Hiatt
	Quadrilaterals formed by using trisection points of the sides
	of a quadrilateral.
	65, (1972)  595 - 600.

That Area Problem
Benjamin Greenberg
	Finding the area of a quadrilateral formed by using trisection points
	of the sides of a quadrilateral.
	64, (1971)  79 - 80.

Some Results On Quadrilaterals With Perpendicular Diagonals
Steven Szabo
	Characterization of such quadrilaterals, uses vector techniques.
	60, (1967)  336 - 338.

The N-Sectors Of The Angles Of A Square
James R. Smart
	Extension of the concepts involved in Morley's theorem.
	60, (1967)  459 - 463.

What Is A Trapezoid?
David L. Dye
	Is a parallelogram a trapezoid?
	60, (1967)  727 - 728.

What Is An Isosceles Trapezoid?
Don E. Ryoti
	Is a parallelogram an isosceles trapezoid?
	60, (1967)  729 - 730.

What Is A Quadrilateral?
Denis Crawforth
	Reprint from Mathematics Teaching.  Activities concerning four points.
	60, (1967)  778 - 781.

What Is A Trapezoid?
M. L. Keedy
	A parallelogram should be a trapezoid.
	59, (1966)  646.

A Unit In High School Geometry Without The Textbook
Paul W. Avers
	Application of discovery methods to the study of quadrilaterals.
	57, (1964)  139 - 142.

Discovering The Centroid Of A Quadrilateral By Construction
Samuel Kaner
	With a suggestion for generalization.
	57, (1964)  484 - 485.

Optional Proofs Of Theorems In Plane Geometry
Francis G. Lankford, Jr.
	Parallels, angle sum of a triangle.
	48, (1955)  578 - 580.

Parallelogram and Parallelepiped
Victor Thebault
	Theorems concerning diagonals.
	47, (1954)  266 - 267.

A Skew Quadrilateral
Mathematics Laboratory (Monroe High School)
	Construction of a model.
	46, (1953)  50 - 51.

A Parallelogram Device
M. H. Ahrendt
	The construction and uses of a linkage.
	43, (1950) 350 - 351.

Functional Thinking In Geometry
Hale Pickett
	Some results concerning the consequences of joining the midpoints of
	the sides of a quadrilateral.
	33, (1940)  69 - 72.

The Story Of The Parallelogram
Robert C. Yates
	Parallelograms and linkages.
	33, (1940)  301 - 309.

H.J.L.
07/15/97
email:  00hjludwig@bsu.edu
home page: http://www.cs.bsu.edu/~hjludwig/