Unit 6
Geometry
In previous grade, Everyday Mathematics proceeded from children’s
experiences with the everyday world to idealized 3-dimensional shapes.
Beginning with this unit, the order is reversed. In this unit, children will
start with points and then move on to line segments, rays, and lines. Then
they will explore the relationship among segments, rays, and lines as well as
the geometric figures that can be built from them, including angles,
polygons, and frames for prisms and pyramids. Unit 6 has three main areas
of focus:
 To investigate line segments, rays, and lines,
 To explore polygons, including triangles and quadrangles, and
 To draw and measure angles.
Vocabulary
Apex – In a pyramid or cone, the vertex opposite the base. In a pyramid, all
the faces except the base meet at the apex.
2-Dimensional (2-D) Shape – A shape with length and width, but no
thickness.
3-Dimentional (3-D) Shape – A shape with length, width, and thickness.
Cone – A 3-dimensional shape with a circular base, a curved surface, and
one vertex. An ice cream cone is shaped like a cone.
Cylinder – A 3-dimensional shape with two circular bases that are parallel
and congruent and are connected by a curved surface. A soup can is shaped
like a cylinder.
Face – A flat surface on a 3-dimensional shape.
face
Intersecting - Two lines or line segments that meet or cross.
Parallel – Lines in a plane that never meet. Two parallel lines are always
the same distance apart.
Polyhedron – A 3-dimensional shape whose surfaces (called faces) are all
flat and formed by polygons. A polyhedron does not have any curved
surfaces.
Prism – A polyhedron with two parallel bases that are the same size and
shape. A prism is named for the shape of its base, and the other faces are all
parallelograms.
Pyramid – A polyhedron with a polygon for a base and the other faces are
all triangles with a common vertex called the apex. A pyramid is named for
the shape of its base.
Sphere – A 3-dimensional shape whose curved surface is, at all points, a
given distance from its center point. A ball is shaped like a sphere.
Vertex (vertices) – A point where the sides of an angle, the sides of a
polygon, or the edges of a polyhedron meet; any corner of a solid.
vertices
Games
Number Top-It (Decimals) - Student Reference Book, page 305
This game provides students with the opportunity to practice comparing
decimals.
Name That Number - Student Reference Book, pages 299-300
This game provides practice with extending facts.
Beat the Calculator (Multiplication) - Student Reference Book, page 279
Students will practice multiplication facts while playing this game.
Angle Race - Student Reference Book, pages 271-272
Students practice measurement skills by playing this game.
Websites
This web site has flash cards for reviewing geometry terms:
http://www.aplusmath.com/cgi-bin/flashcards/geoflash
This website has some interesting information and activities about polygons,
symmetry, and tangrams:
http://library.thinkquest.org/J002441F/activiti.htm
Practice geometric terms by playing concentration, matching, flash cards, or
word search:
http://www.quia.com/jg/65535.html
This site is terrific for answering questions about triangles and
quadrilaterals:
http://www.coolmath.com/reference/geometry-trigonometry-reference.html
Do Anytime Activities
To work with your child on the concepts taught in this unit and in previous
units, try these interesting and rewarding activities:
 Together, read the book The Greedy Triangle by Marilyn Burns.
 Begin a Shapes Museum at home. Label the shapes that your child
collects.
 Ask your child to identify 2-dimensional and 3-dimensional shapes
around the house.
 Measure objects to the nearest ½ inch.
Recommended Reading
Lao Lao of Dragon Mountain by Margaret Bateson-Hill
Opt: an Illusionary Tale by Arlene and Joseph Baum
The Greedy Triangle by Marilyn Burns
Cubes, Cones, Cylinders and Spheres by Tana Hoban
The Art of Shapes: For Children and Adults by Margaret Steele and Cindy
Estes
If You Look Around You by Testa Fulvio
Grandfather Tang’s Story-A Tale Told With Tangrams by Ann Tompert