Education Technology


Published on 06/09/2008

Activity Overview

In this activity, students investigate properties of triangles by randomly generating possible side lengths for triangles. They learn to determine if three line segments can form a triangle. They also learn to classify triangles as acute, obtuse, right, scalene, isosceles, and equilateral triangles. They gain an understanding of the Pythagorean theorem.

Before the Activity

  • See the attached PDF file for detailed instructions for this activity
  • Print pages 13 - 18 from the attached PDF file for your class
  • During the Activity

    Distribute the pages to the class.

    Follow the Activity procedures:

  • Randomly generate 3 numbers between 1 and 6 using the roll dice program on the calculator
  • Use the three numbers as side lengths, cut straws to form these lengths and create a triangle
  • Keep a tally of the three numbers that could be used to make triangles and those that could not make a triangle
  • Classify triangles as equilateral if all sides are congruent, as isosceles if two sides are congruent, and as scalene if no two sides are congruent
  • Classify the triangles as acute if all angles of the triangle are below 90 degrees
  • Classify the triangle as obtuse if triangle has an angle greater than 90 degrees and has 2 acute angles
  • Classify triangles as right triangles if the triangle has an angle of 90 degrees and two acute angles
  • Test for a Pythagorean triplet using the side lengths of different triangles and find the right, acute, and obtuse triangles
  • Combine class data and create a list of all triangles (28 triangles) possible with a side of 1", 2", 3", 4", 5", and 6"
  • Use the triangle inequality rule to test the triangles
  • Classify the triangles by their sides and angles
  • After the Activity

    Students will complete the Worksheet and analyze the results.

    Review student results:

  • As a class, discuss questions that appeared to be more challenging
  • Re-teach concepts as necessary