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Elementary Archive

Browse Elementary 3D and Higher Geometry
Stars indicate particularly interesting answers or good places to begin browsing.

Selected answers to common questions:
    Do cones or cylinders have edges?

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Area and Volume [04/10/2002]

I cannot figure out how to do volume.

Bases and Faces [12/05/2001]

I can't figure out the difference between a base and a face on the shapes we are learning.

Cutting a Cake into 8 Pieces with 3 Cuts [09/08/2002]

How do you cut a cake into 8 pieces making only 3 cuts? How do you cut a doughnut into 12 pieces with only 3 cuts?

Cylinders and Elephants [05/30/1997]

Why are cans always manufactured as cylinders? Are the volume of an animal and the surface area of its feet related?

Defining a Sphere [12/1/1994]

We have two math textbooks from different years that give different information about spheres. One says a sphere has one curved face and the other says it has zero. Is one right and the other wrong or has the definition changed?

A Definition of Geometry [2/1/1996]

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

Definitions of Cones and Cylinders [03/02/2004]

Are cones and cylinders pyramids, prisms or neither? My 5th grade geometry class cannot reach an agreement on this subject!

Distance Between Opposite Corners of a Box [05/09/2002]

A moth is sitting in the lower left front corner of a storage shed. What is the length of the shortest path that the moth can fly to the upper right back corner of the shed?

Does a Sphere have Sides? [04/20/2001]

How many sides does a sphere have?

Edge of a Cube Given Volume [10/06/1997]

I am a teacher currently teaching volume to a class of Grade 5 pupils.

Edges vs. Corners [04/18/2002]

My students get confused on how to determine an edge versus a corner, and counting the number of edges on a geometric figure, say a cube.

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.

Is a Sheet of Paper a 2D or 3D Object? [05/17/2008]

Our teacher said that a piece of paper is a two-dimensional object that has no height, but some of my classmates and I disagree. We think a piece of paper still has a height, even if it is very, very, small, and that it is therefore a three-dimensional object. Who's right?

Length or Width? [12/02/2003]

Can you please explain the difference between height, length, width and depth? Is it always the same for each thing?

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?

Relative Motion on Face of Earth [05/06/2007]

If I am traveling along the earth's surface at the same rate of speed that the earth is rotating in the opposite direction then would I appear to not be moving if you watched me from space?

Surface Area of a Box [03/06/2003]

How do you find the surface area of a box?

What is a Torus? [11/30/1999]

Is there a good way to describe a torus to a child?

What is Geometry For? [03/01/2002]

What is geometry really for?

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