1. Warm Up
How many corners does the tissue box have? How many flat surfaces? How many folded creases?
Draw a net for the tissue box.
Corners: 8
Flat Surfaces: 6
Creases: 12

2. Space Figures and Cross Sections
Objectives:
To recognize polyhedrons and their parts.
To visualize cross sections of space figures.

3. Vocabulary^ Why do we study the parts of a ployhedron?
We can analyze a three-dimensional figure by using the relationship among its vertices, edges, and faces.
polyhedron

4. Problem1~

5. Euler’s Formula

6. Using Euler’s Formula 12 30

7. Practice*

8. Cross Section~

9. Practice*

10. Drawing a Cross Section

11. Practice*

12. Homework
P692: 6, 8, 9, 11, 12, 14, 18-23