1. Nets & Drawings for Visualizing Geometry Section 1-1

2. Vocab Polyhedron - 3-dimensional figure whose surfaces are polygons Face of polyhedron - each polygon that forms the polyhedron Edge - segment formed by the intersection of two faces Vertex - point where 3 or more edges intersect

3. Vocab Ctd.

4. Net - 2-dimensional pattern that you can fold to form a 3-dimensional figure

5. Identifying a Net Is the pattern a net for a cube? If so, name two letters that will be on opposite faces. The pattern is a net because you can fold it to form a cube. Fold squares A and C up to form the back and front of the cube. Fold D up to form a side. Fold E over to form the top. Fold F down to form another side. A and C are the back and front faces. After the net is folded to form a cube, the following pairs of letters are on opposite faces: B and E are the bottom and top faces. D and F are the right and left side faces.

6. You try

7. Drawing a Net Draw a net for the figure with a square base and four isosceles triangle faces. Label the net with its dimensions. Think of the sides of the square base as hinges, and “unfold” the figure at these edges to form a net. The base of each of the four isosceles triangle faces is a side of the square.

8. New Vocab Isometric drawing - shows 3 sides of a 3-dimensional object from a corner view Orthographic - presents a 3- dimensional figure as a top view, front view, and right side view

9. Isometric Drawing Make an isometric drawing of the cube structure below. You will draw all the edges of the figure that you can see.

10. Start by drawing the front face of the figure. Next, draw the back edges of the figure. Finally, fill in the right face, top faces, and left edges. (continued)

11. You try Create an isometric drawing of the figure

12. Orthographic Drawing Make an orthographic drawing of the isometric drawing below. Orthographic drawings flatten the depth of a figure. An orthographic drawing shows three views. Because no edge of the isometric drawing is hidden in the top, front, and right views, all lines are solid.

13. You try Make an orthographic drawing from the isometric drawing.

14. Closure Explain how isometric & orthographic drawings are alike and how they are different. All show 3-d figures on a 2-d surface; isometric drawings show 3 faces, while orthographic drawing show the outlines of 3 views.