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Browse Middle School Triangles and Other Polygons
Stars indicate particularly interesting answers or
good places to begin browsing.
Selected answers to common questions:
Classifying quadrilaterals.
Polygon diagonals.
Pythagorean theorem proofs.
 Naming Corresponding Parts of Congruent Figures [04/23/2003]

Given triangle OPS congruent to triangle TQR, name the corresponding
sides and angles of the two triangles.
 Naming Polygons [5/30/1995]

Could you please give me a complete list of polygon names from 3  100?
 Naming the Isosceles Triangle [09/23/1998]

How did the isosceles triangle receive its name?
 Nonagon or Enneagon? [02/06/2003]

Is 'enneagon' really the correct name for a 9sided polygon?
 Number of Points in a Star [7/16/1996]

Is there a way to predict the number of points in a star given only the
internal angle of the corners?
 One and Twosided Polygons [12/07/1999]

Can you explain what a monogon and a digon are?
 On Polygons, Polygons within Polygons, and Definitions [07/22/2010]

If we cut one polygon out of the interior of another, is the resulting shape a polygon?
Doctor Peterson gives a curious student a better definition than he found in his book,
pointing out the importance of separating polygons from their interiors  and of
experimenting with definitions.
 Origami Equilateral Triangle [04/26/2001]

How can I create an equilateral triangle from a piece of paper using only
origamilike folds?
 Origin, Meaning of 'Hypotenuse' [9/13/1996]

What is the origin and meaning of the term "hypotenuse"?
 Parallelogram Perimeter [10/01/1997]

The diagonals of a parallelogram are 10 and 24 in length. If one side of
the paralellogram is 13, what is the perimeter?
 Pentagram [12/08/2001]

Is a fivepointed star on a flag a decagon? Or just five triangles?
 Perimeter of Two Similar Objects [2/16/1996]

Why do you lose area in a 4 x 12 rectangle as compared to an 8 x 8
square? Each has the same perimeter.
 Picture of Icosahedron [7/31/1996]

Do you have a picture of an icosahedron?
 Pipe Needed for Natural Gas Line [09/03/1997]

Two houses are 130 metres apart at distances of 55 and 105 metres...
 Placing Coins That Touch [8/7/1996]

How many 20cent coins can you put around a 20cent coin so that all of
them touch?
 Pole in a Box [02/09/1999]

Can a pole 6.5m long fit into a truck with dimensions of 3m, 3.5m, and
4m?
 Polygon Diagrams [05/11/2003]

I would like to see pictures of polygons with 11, 12, 13, 14, and 15
sides.
 Polygon Names [09/18/2001]

Why is a 3sided polygon called a triangle instead of a trigon? Why is a
4sided polygon called a quadrilateral instead of a tetragon, when all
the others are ___gons? Why is there not a single consistent term?
 Polygon Names II [12/11/2003]

Why is the triangle named "triANGL"', unlike all the other polygons, which have names like "quadriLATERAL" or "pentaGON"?
 Polygons and Circles [4/3/1996]

Is a circle a polygon? Why or why not?
 Polygons, Infinite Sides, and Circles [04/03/1997]

Can a regular polygon with an infinite number of sides be a circle?
 Polyominoes [09/08/1997]

I am using polyominos, but I do not know how to tell my dad what they
are. How can I tell him so he will know?
 Proof of Pythagorean Theorem: Pythagoras' Reasoning [02/23/1998]

I would like to know how Pythagoras reasoned his theorem.
 Proofs with Isosceles Triangles [10/28/1998]

What are altitudes, angle bisectors, and medians? How do you prove that
in an isoseles triangle, the altitude is a median and an angle bisector?
 Properties of Equilateral Triangles [07/20/1998]

If ABC is equilateral and AD is one of its heights, what are the measures
of the angles? Is ADB equal to ADC? If AB = 2 find BD and AD.
 Prove Triangles are Similar [12/16/1995]

How do you prove two triangles are similar?
 Pythagorean Theorem [1/19/1995]

What is the Pythagorean Theorem?
 Pythagorean Theorem [7/19/1995]

How come a^2 + b^2 = c^2?
 Pythagorean Theorem [5/14/1996]

What is the Pythagorean theorem?
 The Pythagorean Theorem: A Modern Proof [04/14/1997]

I know that the Pythagorean Theorem works and I can show how it works,
but why does it work?
 Pythagorean Theorem Legend [01/31/2009]

Is there a Sioux Indian legend that refers to the Pythagorean Theorem?
 Pythagorean Theorem Proof by Brodie Explained [03/15/2000]

Could you give me a stepbystep explanation of Dr. Scott Brodie's proof
of the Pythagorean theorem given at the cuttheknot website?
 Pythagorean Theorem Proof: Four Right Triangles [10/7/1996]

I don't understand the Pythagorean Theorem.
 Pythagorean Triples [04/14/1997]

Why can't all the numbers in a Pythagorean triple be prime?
 Quadrilateral Classification: Definition of a Trapezoid [01/15/1997]

What is the correct definition of a trapezoid, and why?
 Quadrilateral Patterns [03/06/1997]

What is the formula that gives the number of quadrilaterals within a
square grid when you increase the square grid by one unit on each side?
 Quadrilaterals [8/31/1995]

What is 4sided and has no equal angles?
 Ratio and proportion [12/5/1994]

I need extra help in ratio and proportion.
 Ratio of Sides and Ratio of Areas [02/11/1999]

If the sides of a triangle are in the ratio of 1:7, what is the ratio of
their areas? What about for other shapes?
 Ratios and Geometry [10/29/1998]

An airplane flying at 33,000 feet has a visibility of 100 miles. What
percent of the total land area to the horizon is visible?
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