Education Technology

Geometry: Slices
by Texas Instruments

Updated on January 14, 2015


  • Students will predict and identify the shapes of two-dimensional cross-sections that are formed when three-dimensional figures are cut by horizontal and vertical planes.
  • Students will draw, construct, and describe geometrical figures and describe the relationships among them.


  • rectangular prism
  • triangular prism
  • square pyramid
  • tetrahedron
  • cylinder
  • cone

About the Lesson

This lesson involves exploring the shapes formed from 3D figures cut by a horizontal and/or a vertical plane.
As a result, students will:

  • Predict the outcomes of moving planes through 3D figures.
  • Move a horizontal and vertical plane through the figure to check their predictions.
  • Explain any similarities or differences they see in the shapes that are formed as the planes move through the figure.
  • Determine what 3D figure was sliced. given a description of the shapes formed from slicing the figure both horizontally and vertically.