1. 12.1: Representations of Three-Dimension Figures
Objectives
Identify the shapes of two0dimensional cross-sections of three dimensional objects
Identify three-dimensional objects generated by rotations of two-dimensional objects

2. Math Short Video

3. Vocab The intersection of a solid and a plane. Cross Section
Types of Slice

4. Examples Example 1 Example 2 Example 3 Ellipse Rectangle Circle
Imagine you were to cut through this figure, if you were to pull it apart what shape would it make?
Rectangle
Ellipse
Circle

5. You try
Describe the shape resulting from a vertical, angled, and horizontal cross section of a square pyramid. Vertical: Angled: Horizontal:
Triangle
Trapezoid
Square

6. Example 4
A customer ordered a two-layer sheet cake. Determine the shape of each cross section of the cake below.
Rectangle

7. Example 5 Determine the shape of the cross section shown. a) b)
Trapezoid
Triangle

8. You Try Describe the shape resulting from each cross section. a) b) c)
Do on your own!