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Triangle Sum Theorem

Interior angles add to 180 degrees

Atoms Practice
Estimated6 minsto complete
Practice Triangle Sum Theorem
Estimated6 minsto complete
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Triangle Sum Theorem
teacher Contributed

RWA Triangle Sum Theorem


Spherical Geometry


  • triangle sum theorem
  • comparing angles and sides in triangles
  • sphere
  • Spherical Geometry

Student Exploration

Do the angles in a triangle always add up to 180 degrees? How are the lengths of the sides of a triangle are controlled by the sizes of the angles in Spherical Geometry?

Watch the video below to learn more


Extension Investigation

  1. Students can make a presentation like the one below http://www.youtube.com/watch?v=b7DmUymGR28&feature=related
  2. Virgo is one of the constellations of Zodaic. Three principal stars of the constellation form a triangle. If \begin{align*}m \angle S = 25\end{align*} and \begin{align*}m \angle P = 135\end{align*}, then find the \begin{align*}m \angle V\end{align*}. http://worksheets.tutorvista.com/angles-in-a-triangle-worksheet.html

Layering (optional)

How do we show that all of the angles the triangle add up to 180?

Watch these videos to see how

Image Attributions

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