Purpose: Students will use simple objects of a small business
envelope and a lunch bag to fold to create various geometric
shapes and investigates various geometric concepts. Materials
Needed: Small business envelopes, brown paper lunch bags,
scissors, tape, rulers, coloring pencils. Part One, the
Envelope: 1. Take a small business envelope and seal it.
Calculate the surface area of the envelope. 2. Draw the
diagonals of the rectangle with a straight edge. 3. Fold across
one of the diagonals and crease the fold. 4. Fold across the
other diagonal and crease the fold. 5. Identify and classify all
of the triangles that can be seen on the side of the diagonals.
Answer: Four congruent right triangles, two pairs of congruent
isosceles triangles (one pair equilateral, one pair obtuse). 6.
Cut out one of the obtuse isosceles triangles. 7. Pull out from
the vertex of the isosceles cut, and stuff one end inside the
other to create a tetrahedron. 8. Identify the number of faces
and determine if it is a regular polyhedro