SIDES OF A TRIANGLE
Instructions
Introduction
What makes a triangle a triangle?
What makes a triangle a unique triangle – one of a kind?
It’s all about sides and angles.
In this activity you will explore the sides of a triangle, noticing when a set of sides, line segments, can determine a unique triangle, more than one triangle, or no triangle at all.
In the GeoGebra workspace, there are three sets of sides that can be used to attempt to construct triangles in the open workspace: Set A, Set B, and Set B.
The red line segments are of fixed length.
The black line segment has an adjustable length, changed by dragging the black endpoint.
They can be moved about the workspace using the blue endpoint.
They can be swiveled using the orange endpoint.
Step 1
Use the MOVE tool to drag and manipulate line segments in Set A onto the open workspace. Try to make a triangle with the given segments as sides. Connect the end-points are carefully as you can. Can you construct a triangle with these three line segments? Explain your answer.
Step 2
Move the line segments from Set A back into their box. Use the MOVE tool to drag and manipulate line segments in Set B onto the open workspace. Try to make a triangle with the given segments as sides. Connect the end-points are carefully as you can. Can you make a triangle with these three line segments? Can you make more than one?
Step 3
Move the line segments from Set B back into their box. Use the MOVE tool to drag and manipulate line segments in Set C onto the open workspace.
Try to make a triangle with the given segments as sides.
Can you make a triangle with these three line segments?
Can you make more than one? How many?
Conclusion
Summarize what you have learned about the sides of triangles and whether or not, given a set of sides, you can create triangle, more than one triangle, or no triangle at all.