Education Technology

Geometry: Exploring Diagonals of Quadrilaterals

by Texas Instruments


  • Demonstrate knowledge and understanding of the nature of different quadrilaterals based directly on the properties of their diagonals
  • Identify quadrilaterals given only properties of their diagonals


  • diagonal
  • vertex angles
  • perpendicular bisector

About the Lesson

This lesson involves manipulating endpoints and/or the intersection point of two diagonals that have special characteristics. As a result, students will:

  • Observe whether the two diagonals mutually bisect each other, bisect vertical angles, are congruent, or whether one is the perpendicular bisector of the other.
  • Determine which special quadrilaterals can be formed and, in some cases, determine which special quadrilateral must be formed, based on what they know about the diagonals.