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Angles in Triangles

This topic deals with finding the unknown angles in a triangle using the Triangle Sum Theorem.

Topic: Angles in Acute, Right, and Obtuse Triangles

  • The angle measures of a triangle add to 180°. This is known as the Triangle Sum Theorem

  • An acute triangle has 3 acute angles

  • A right triangle has 1 right angle

  • An obtuse triangle has 1 obtuse angle

Topic: Angles in Equilateral, Isosceles, and Scalene Triangles

  • The angle measures of a triangle add up to 180°. This is known as the Triangle Sum Theorem

  • An equilateral triangle has 3 congruent sides and 3 congruent angles

  • An isosceles triangle has at least 2 congruent sides and 2 congruent angles

  • A scalene triangle has no congruent sides and no congruent angles

Topic: Angles That Meet Given Conditions

  • The angle measures of a triangle add up to 180°. This is known as the Triangle Sum Theorem
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