Classifying triangles

Lessons

• Introduction
  a)

  Naming types of triangles based on their properties

  1. By angles
  • Acute
  • Right
  • Obtuse
  2. By sides
  • Scalene
  • Isosceles
  • Equilateral
  
  

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• 1.
  Classify the triangle by its sides and angles.
  a)

  
  
  
  
  
  b)

  
  
  
  
  
  c)

  
  
  
  
  
  d)

  
  
  
  
  

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• 2.
  Draw and classify the triangle by its vertices. Then, determine if it is a right triangle.
  a)

  A(3, 6), B(3, 1), C(9, 1)
  
  
  b)

  A(2, 4), B(5, 10), C(5, -2)
  
  
  c)

  A(8, 7), B(11, 3), C(4, 2)
  
  

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• 3.
  Find x. Then, classify the triangle by its angles.
  a)

  
  
  
  
  
  b)

  
  
  
  
  
  c)

  
  
  
  
  

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• 4.
  One angle of a triangular chocolate box is 20°. The measure of the second angle is 3 times smaller than the third one. Find the measures of the two unknown angles.

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