Warm Up Week 6

Section 12.1 Day 1 I will use the properties of polyhedra. Cross section The intersection of a plane slicing through a solid. The cross section is a circle.

Describe the cross section:Do 1:

Platonic Solids 5 special regular polyhedra. Don’t Write

Euler’s Theorem The sum of the faces (F), vertices (V), and edges (E) of a polyhedron are related by the formula: F + V = E + 2. Theorem 12.01

Rule 1 In a solid, each side is shared by exactly 2 polygons. 8 triangles, 6 octagons = 14 faces F + V = E V = E (3), 6 (8) = 72 edges = 36 edges 14 + V = V = 38 V = 24 Ex 1

Ex 2 20 Hexagons 12 Pentagons x 6 x 5 edges Find the number of vertices:

Assign ment: Textbook Page 723, 10 – 24 all. Do 1: How many faces, edges, and vertices?