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Elementary Archive

Browse Elementary Two-Dimensional Geometry
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Selected answers to common questions:
    What are length and width?

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Angles: Acute, Right, Obtuse, Reflex [06/06/2001]

How can I remember what the names of angles mean?

Area and Perimeter [05/01/2001]

I do not understand area and perimeter - can you explain them?

Area and Volume [04/10/2002]

I cannot figure out how to do volume.

Turning a Perimeter into a Scale Factor [02/17/2003]

Perimeter and area ratios of similar figures are given. Find each scale factor.

Using a Protractor [06/28/1998]

How do you construct two parallel lines and intersect them making a 65-degree angle?

A 14-Sided Polygon [7/28/1996]

What is the proper name for a 14-sided figure?

2 Square Feet vs. 2 Feet Square [11/22/1998]

What is the difference between 2 square feet and 2 feet square?

7-, 9-Sided Polygons [9/13/1996]

What is the name of a 7-sided figure? a 9-sided figure? Is one of these ever called a septagon? If "septi" means seven, why is September the 9th month of the year?

Adjacent Angles [09/19/2001]

What is the definition of adjacent angles?

Area Larger Than Perimeter? [04/15/2002]

Can the area of a shape be larger than the perimeter?

Area of an L [07/10/2003]

How do you find the area of an 'L' shaped object?

Areas of Figures Broken into Rectangles [10/17/2001]

Calculate the area of each figure. First divide the figure into rectangles and squares...

Area: Triangle vs. Rectangle [4/30/1996]

Why do you have to use a different formula to get the area of a triangle than a rectangle or square?

Area vs. Perimeter of Rectangles [03/19/2000]

Can you explain how two rectangles with exactly the same perimeter can enclose different areas?

Circle Area and Circumference [03/16/2002]

Are radius and diameter the same as area and circumference?

Circumference vs. Perimeter [05/09/2003]

Technically speaking, can the term 'perimeter' apply to a circle in a mathematical context?

Complementary or Supplementary? [04/02/2001]

I keep getting complementary and supplementary mixed up. How can I remember which is which?

Coordinates in the Cartesian Plane [01/21/2005]

How do I get the coordinates for a point on a graph?

Cutting Slits in a Piece of Paper [02/01/2002]

How can you cut a hole in a piece of paper so a person can go through it?

A Definition of Geometry [2/1/1996]

A fifth grader asks Dr. Math to give her a definition of geometry.

Deriving the Area Formula for a Circle [03/08/2000]

Why is the area of a circle the square of the radius times pi?

Dividing Land by Area vs. Perimeter [11/05/1999]

What are the advantages of dividing land by area vs. perimeter?

Eleven Sections of Fence [05/29/2003]

I have a grid containing 16 squares. Each square represents 1 acre. I need to draw 11 sections of fence along the dotted lines of the squares so that 4 fields are formed, each containing 4 acres of land.

Equable Shapes [04/26/2001]

Is there a rule for how to get equable shapes, that is, shapes with the same area and perimeter?

Euler's Formula [11/26/2001]

I have to find Euler's formula for two-dimensional figures and explain it at a university level and at an elementary-school level.

Figuring Square Footage and Yardage [12/14/2002]

What is the exact calculation used in order to determine square footage or yardage of a given room?

Flatland, by Edwin Abbott [8/21/1996]

I need any info about the book FLATLAND by Edwin Abbott and how it can be used in the classroom.

Flips, Reflections, Rotation, and Quadrants [11/10/1998]

These terms are being used to describe the movement of shapes. What do they really stand for?

Fourth Grade Geometry Questions [4/24/1995]

My grade 4 regular education students are wondering if curved lines can be parallel lines.

Geometric Objects [4/1/1996]

Name objects in the real world that suggest geometric figures, including lines and planes.

Intersection of Circles [10/08/1998]

I do not understand the term intersection in geometry.

Learning Proofs [12/19/1995]

I'm a fourth grader interested in learning how to do proofs. Can you recommend some good books on the different techniques used and how they are applied?

Left Angles [06/01/1999]

What is a left angle?

Line Segments and the Origins of Geometry [6/7/1995]

How can segments be lines? Why is geometry called geometry?

Mobius Strips, Spheres, and Dimensionality [05/28/2003]

Is a Mobius Strip 2-D or 3-D? Or is it 1-D? What about a sphere?

Obtuse angles [11/10/1994]

What is an obtuse angle?

One Dimension [05/13/2003]

Is there such a thing as 1D?

Planting Trees [08/13/2002]

I have to plant 10 trees in 5 rows with 4 trees in each row.

Polyominos [08/11/1999]

What is the definition of a polyomino?

Rays and Angles [11/24/1997]

Do rays have an arrow on both ends, or is that an angle?

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