Education Technology

Geometry: The Mailbox

by Texas Instruments


  • Students will use volume formulas to solve problems.
  • Students will recognize that the area of a composite shape is the sum of the areas of its smaller parts.
  • Students will determine the area of an irregular shape by decomposing it into geometric figures whose areas they can calculate.
  • Students will model with mathematics.

About the Lesson

In this lesson, students will visualize that areas of irregular shapes can be found by determining the sum of smaller, more familiar shapes.

  • Student may use the Measurement tools found in the Geometry menu options or model the image using functions on the Graphs page.
  • Teachers and students can use the TI-Nspire software or iPad app to investigate objects in their own photographs and use proportions to adjust the scale before making measurements to use in calculations with TI-Nspire.