Tuesday,  February 21

Project reminder: Proposals due Wednesday.

Review of last class end of discussion:
What does a folded down flattened torus look like?
A rectangle with opposite sides resulting from cutting the torus open making a cylinder and then cutting the cylinder along its length.

    A torus

Torus



Analogy: A Conceptual Tool
  point... line.... polygon.... polyhedron......



Next class we will see how this formula can help solve some problems on the plane and elsewhere.