Triangles (Jump to: Lecture | Video )
| Triangle | 
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 A triangle is a shape made up of three line segments which intersect at their endpoints. 
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The three angles of any triangle add up to 180 degrees.
Triangles can be classified as Right Triangles, Acute Triangles, or Obtuse Triangles.
| Right Triangle | 
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 A Right Triangle is a triangle with one right angle. 
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| Acute Triangle | 
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 An Acute Triangle is a triangle with all acute angles. 
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| Obtuse Triangle | 
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 An Obtuse Triangle is a triangle with one obtuse angle. 
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Triangles can also be classified by the length of their sides. There are Equilateral Triangles, Isoceles Triangles, and Scelene Triangles.
| Equilateral Triangle | 
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 An Equilateral Triangle is a triangle with all thee sides equal. 
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| Isoceles Triangle | 
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 An Isoceles Triangle is a triangle with two equal sides. 
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| Scalene Triangle | 
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 A Scalene Triangle is a triangle with no equal sides. 
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