Definition of Obtuse Angle

Any angle greater than 90� and smaller than 180� is called an Obtuse Angle.

More About Obtuse Angle

  • An angle of 90� is called a right angle.
  • An angle of 180� is called a straight angle.

Example of Obtuse Angle

    The angle shown in the figure is greater than 90� but smaller than 180�, so it is an obtuse angle.

Video Examples: Acute and Obtuse Angles in Geometry

Solved Example on Obtuse Angle

Ques: Identify the obtuse angle in the given triangle.

    A. ?ACB
    B. ?ABC
    C. ? BAC
    D. ?CAB
    Correct Answer: B


    Step 1: An angle greater than a right angle and less than a straight angle (> 90� and < 180?)="" is="" called="" an="" obtuse="">
    Step 2: In the given figure, ?A and ?C are acute angles and ?B is an obtuse angle.
    Step 3: So, ?ABC is an obtuse angle.

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