Education Technology

Midsegment of a Trapezoid

Subject Area
Math: Geometry: Quadrilaterals
Level
9-12
Activity Time
60 Minutes
Software
TI Connect™
TI Calculator
TI-83 Plus Family
TI-84 series
Other Materials
This is Activity 11 from the EXPLORATIONS Book:
Exploring The Basics Of Geometry With Cabri

Resource Types
Lessons

Midsegment of a Trapezoid

Activity Overview

Students study the Midsegment Theorem for Trapezoids.

Before the Activity

Install the Cabri™: Jr. App on the students' graphing calculators using one of these two methods:

  • TI-Connect™,  a TI Connectivity Cable, and the Unit-to-Unit Link Cable
  • TI-Navigator™  "send to class" feature
  • See the attached PDF file for detailed instructions for this activity
  • Print pages 45 - 47 from the attached PDF file for your class
  • During the Activity

    Distribute the pages to the class.

    Follow the Activity procedures:

  • Construct a segment AB
  • Construct a segment CD parallel to AB (not of the same measure)
  • Construct segments AD and BC to form a trapezoid ABCD
  • Drag point A so that AD is not parallel to BC
  • Construct a midsegment by joining the midpoints of segments AD and BC
  • Alter the trapezoid and check whether the midsegment is parallel to segments AB and CD
  • The midsegment is parallel to the two parallel sides of the trapezoid
  • Measure the lengths of AB, CD, and the midsegment
  • Observe that the length of the midsegment is half the sum of the lengths of AB and CD
  • Alter the trapezoid
  • Observe that for all trapezoids, the length of the midsegment is half the lengths of the two parallel sides
  • After the Activity

    Review student results:

  • As a class, discuss questions that appeared to be more challenging
  • Re-teach concepts as necessary
  • Subject Area
    Math: Geometry: Quadrilaterals
    Level
    9-12
    Activity Time
    60 Minutes
    Software
    TI Connect™
    TI Calculator
    TI-83 Plus Family
    TI-84 series
    Other Materials
    This is Activity 11 from the EXPLORATIONS Book:
    Exploring The Basics Of Geometry With Cabri

    Resource Types
    Lessons
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