📚 Practice With Worksheets
Extend your learning by exploring triangle angle relationships, constructing valid triangles, and finding missing angle measures.
🛠️ How to Use This Tool
Drag any vertex of the triangle or adjust the angle sliders to change the shape of the triangle. As the triangle changes, watch how the measures of the three interior angles change as well.
Observe the angle measures displayed for Angles A, B, and C. Notice that even though the individual angle measures change, the total always remains the same.
This tool is ideal for exploring the Triangle Angle Sum Theorem, making conjectures, and helping students discover why the interior angles of every triangle add up to 180 degrees.
🧠 Things to Think About
What happens to the other two angles when one angle increases? Can a triangle have three right angles? Why does the angle sum remain constant even when the shape of the triangle changes? What is the largest possible measure of one angle in a triangle?
📘 Vocabulary
Vertex: The point where two sides of a polygon meet.
Angle: The figure formed by two rays that share a common endpoint.
Interior Angle: An angle located inside a polygon.
Degree: A unit used to measure the size of an angle.
Triangle Angle Sum Theorem: The interior angles of any triangle always add up to 180°.
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