1. Ice cream factories test how consistently the ingredients are distributed through each carton by cutting cartons in half for a good view. Describe the 2D figures that result from slicing a carton vertically or diagonally through the top & side. How do you determine the shape that results from slicing a 3D solid?

2. In this lesson, you will learn how to visualize the 2D cross- sections of cylinders by analyzing if a plane intersects with straight or curved surfaces.

3. Core Lesson Effect of slicing plane Where a plane intersects faces, a 2D figure results

4. Let’s Review Identify characteristics of the solid Bases Lateral surface (face) Edges

5. Core Lesson Distance from center is constant. Therefore it’s a circle Horizontal Cross-section r r Slices parallel to base are congruent to base

6. Vertical Cross-section Vertical slice always creates a parallelogram

7. A Common Misunderstanding A diagonal cross-section creates a circle Circles are only created by horizontal cross-sections

8. Core Lesson Distance from center is not constant Actually an ellipse Diagonal Cross-section b a

9. Core Lesson Diagonal Cross-section Types of faces intersected determines types of edges on 2D figure

10. Intersects 2 arcs & 2 parallel lines Diagonal Cross-section

11. Core Lesson Ice cream factories test how consistently the ingredients are distributed through each carton by cutting cartons in half for a good view. Describe the 2D figures that result from slicing a carton vertically or diagonally through the top & side. Vertical: rectangle Diagonal: half-moon

12. In this lesson, you have learned how to visualize the 2D cross- sections of cylinders by analyzing if a plane intersects with straight or curved surfaces.