Angles in a triangle
Angles in a triangle is an interactive experiment in Plane Geometry, a free simulation from StudyFi Lab that runs right in your browser.
The interior angles of every triangle add up to 180°. A line through C parallel to AB shows why: the angles α and β reappear at C as alternate angles.
Try this: Drag the vertices — the three angles change, their sum stays 180°.
Frequently asked questions
What does the “Angles in a triangle” experiment show?
The interior angles of every triangle add up to 180°. A line through C parallel to AB shows why: the angles α and β reappear at C as alternate angles.
How do I try “Angles in a triangle”?
Drag the vertices — the three angles change, their sum stays 180°.
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