Transcript Cube Nets
Name of the section Nets and Drawing for Visualizing Geometry Section Objectives Objective To make nets and drawing of three-dimensional figures Materials Needed • Graph paper • Isometric drawing paper • Straight Edge Essential Understanding and Definition • Essential Understanding for this section: You can represent a three-dimensional figure using special drawing techniques. • Definition: A net is a two-dimensional diagram that you can fold to form a threedimensional figure. A net shows all of the surfaces of a figure in one view. Identifying a Solid from a Net • Watch the net to the left fold into a cube. • The net below it folds into the cube shown beside it. • Each “cube” net has how many squares (sides)? – six • These are two examples of a net for a cube. • How many ways are there to arrange six squares so that they make a cube? Finding all the nets Your job is to find all the different cube nets that are possible. (Two are provided for you!) • each time, you must use all six tiles • if two tiles touch, they must border along a full side Draw each of your solutions on graph paper Let me check to see if it is one we have not done yet. Color it, cut it out and tape it together. Cube Nets Answer 1 5 3 2 7 6 9 4 8 Talk about it • What properties are common to all nets? • What type of nets will not work? Why not? • Without folding, is there a quick way to tell if a net will fold into a cube? • How can you tell if two nets are identical? Sides of the Net E C • Let’s go back to the original net. Which letters will be on the top and front of the cube? • A, C, E, and F all share an edge with D when you fold the net, but only two of those sides are visible n the cube shown. • A wraps around and joins with D to become the back of the cube. • B becomes the left side. F folds back to become the bottom. • E folds down to become the top of the cube. C becomes the front. Got it? • Given this net folds into this cube, which letters will be on the top and right side of the cube? E B C Drawing a Net from a Solid 12” 2.5” 9” • Package designers use nets to design boxes and other containers like cereal boxes. • What is the net for the rectangular prism formed by the box. • Label the net with its dimensions. Drawing a Net from a Solid • Why is the actual box not a net? 2.5” 9” 12” Got it? • What is the net for the figure? • Label the net with its dimensions. • Is there another possible net for the figure? If so, draw it. • Wolfram animation Isometric Drawing • Definition: An isometric drawing shows a corner view of a three-dimensional figure. It allows you to see the top, front, and side of the figure. • You can draw an isometric drawing on isometric dot paper. • The simple drawing of a file cabinet here is an isometric drawing. Visualizing Geometry • A net shows a three-dimensional figure as a folded-out flat surface. • A net shows three-dimensional figure using slanted lines to represent depth. Isometric Drawing • What is an isometric drawing of the cube structure? • Draw the front edges • Draw the right edges • Draw the back edges Got it? • What is an isometric drawing of the cube structure? Solid lines show Going in reverse visible edges. top Dashed lines show hidden edges. Can we take a threedimensional isometric drawing and draw the three two-dimensional views? front The isometric drawing shows the same three views. right Orthographic Drawings • What we just viewed were orthographic drawings. • Definition: An orthographic drawing is another way to represent a threedimensional figure. • An orthographic drawing shows three separate views: a top view, a front view and a right-side view. Get it? • What is the orthographic drawing for this isometric drawing? Classwork and Homework Exit Card 1. Tell whether the figure is isometric, orthographic, a net or none.