This geometry video provides a basic introduction into triangles. It explains how to calculate the measure of an interior angle of a triangle as well as the exterior angle. The sum of all three interior angles is 180. The exterior angle is the sum of the two remote interior angles according to the exterior angle theorem. In addition, this video explains how to calculate the length of the midsegment of a triangle. It contains plenty of examples and practice problems.

Polygons:
   • Polygons  

Quadrilaterals:
   • Quadrilaterals - Geometry  

Skew Lines:
   • Skew Lines, Perpendicular & Parallel ...  

Points, Lines, Planes, & Segments:
   • Points, Lines, Planes, Segments, & Ra...  

Number of a Diagonals In a Polygon:
   • Number of Diagonals In a Regular Poly...  

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Ratios and Proportions - Means Extreme:
   • Ratios and Proportions, Arithmetic & ...  

Similar Triangles:
   • Similar Triangles  

Similar Triangles - Enlargement Ratios:
   • Similar Triangles and Figures, Enlarg...  

Triangle Similarity - SSS, SAS, & AAA:
   • Triangle Similarity - AA SSS SAS & AA...  

Triangle Proportionality Theorem:
   • Triangle Proportionality Theorem, Sid...  

Altitude on Hypotenuse Theorem:
   • Altitude on Hypotenuse Theorem - Geom...  

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Pythagorean Theorem:
   • Pythagorean Theorem  

The Distance Formula:
   • Distance Formula  

Distance Between 2 Points - 3D:
   • How To Find The Distance Between 2 Po...  

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