This tutorial teaches how to construct an isosceles triangle using the TI-Nspire App. The steps include: creating a geometry window, constructing a line segment and finding its midpoint, creating a perpendicular line at the midpoint, constructing the triangle by connecting segments from the midpoint and base, and measuring the side lengths and base angles to show the triangle's isosceles properties.

1. TI-Nspire App Tutorial
Constructing an Isosceles Triangle

2. Summary
• In this tutorial, you’ll be constructing an
Isosceles Triangle. The steps in the tutorial
include:
– Creating a Geometry Window.
– Constructing a line segment and finding its
midpoint.
– Creating a perpendicular line at the midpoint.
– Constructing the triangle.
– Measuring its side lengths and base angles.

3. Create a Geometry Window
Click on the + tool to activate this menu.

4. Create a Geometry Window
This is a blank Geometry Window.

5. Construct a Line Segment
Click on Menu and select Points & Lines > Segment.

6. Construct a Line Segment
Press once to define the left endpoint. Then press again to
define the right endpoint. Make sure it’s horizontal.

7. Find the Midpoint
Press Menu and click Tools > Measurement > Midpoint.

8. Find the Midpoint
Press on the segment to create the midpoint.

9. Construct a Perpendicular Line
Click on Menu and press Perpendicular.

10. Construct a Perpendicular Line
Press on the Midpoint. You can also extend the perpendicular
line by clicking and dragging it.

11. Construct the Triangle Sides
Press on Menu and click Tools > Points & Lines > Segment.

12. Construct the Triangle Sides
Construct the first side by clicking on one endpoint at the base
and creating one on the perpendicular line.

13. Construct the Triangle Sides
Press on the Segment Tool again.

14. Construct the Triangle Sides
Construct the second side by clicking on the endpoint on the
perpendicular line and the other endpoint on the base.

15. Measure the Side Lengths
Press Menu and Click Tools > Measurement > Length.

16. Measure the Side Lengths
Click on a side length. You’ll see the measurement, which you
can move to a different part of the screen.

17. Measure the Side Lengths
Press on Menu and Select Length again.

18. Measure the Side Lengths
Measure the other side. Note that they are congruent.

19. Measure the Base Angles
Press on Menu and Select Angle.

20. Measure the Base Angles
Click on the highlighted points to measure this base angle.

21. Measure the Base Angles
Click on Menu and Angle to measure the other base angle.

22. Measure the Base Angles
Click on the highlighted points to measure this base angle.
Notice the base angles are congruent.

23. Manipulate the Triangle
Click on any of the vertices of the triangle to manipulate.
Notice it maintains congruent sides and base angles.