Education Technology

SA and NT: Triangle Sides & Angles

by Texas Instruments


Students will explore side and angle relationships in a triangle. First, students will discover where the longest (and shortest) side is located relative to the largest (and smallest) angle. Then, students will explore the Isosceles Triangle Theorem and its converse. Finally, students will determine the number of acute, right, or obtuse angles that can exist in any one triangle.

Key Steps

  • Image

    Direct students to measure the three side lengths using the Measure > D. & Length tool. To measure a side of the triangle, you must click on the endpoints of the segment. If you click on the side itself, the tool will return the perimeter of the triangle.

  • Image

    Now students should drag a vertex of the triangle to change the angle measures and side lengths.