## Visualizing Cross-sections in Primitive 3D Shapes

Type: Mini-lesson

Theme: Geometry

Grades: 5, 6, 7, 8, 9, 10

Learning Target: Students will describe the two-dimensional figures that result from slicing three-dimensional figures.

Instructions
1. Demonstrate how to use the OpenSCAD code below to create cross-sections. Explain how to use the Customizer to adjust the rotation and translate variables.
2. Provide students OpenSCAD code. Students may also illustrate on paper or with digital ink.
3. Students will construct cross-sections and create pages in a shared PowerPoint presentation which contain snips of their visualizations.

### SCAD Code for 3D Cross-sections

`//Uncomment the primitive prisms below to see how cross-sections are affected. Adjust the variables below to rotate and translate the slices.//Rotate with values up to 90 (degrees)rotation = 0;//Translate with values up to 20translation=0;intersection(){ rotate([rotation,0,0])translate([0,0,translation-25])color([1,1,1,.1]) cube([50,50,50],center=true);  # //cylinder cylinder(h=20, r=10, center=true);  //cone //cylinder(h=15, r1=10, r2=0, center=true,\$fn=100);  //sphere //sphere( r=10 ,\$fn=100);  //pyramid //rotate([0,0,45]) cylinder(20,20,00,center=true,\$fn=4); }rotate([rotation,0,0])translate([0,0,translation])color([1,.7,.7,.1]) cube([50,50,.01],center=true);`
Exit Ticket
CCSS Math Practice
• I can make sense of problems and persevere in solving them.
• I can use appropriate tools strategically.
NGSS Crosscutting Concepts
• Structure and Function

Group Project