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Home > MC2 > Chapter 9 > Lesson 9.2.2 > Problem 9-54


If each triangle below is drawn accurately, identify whether it is an obtuse, acute, or right triangle. Name the angle or angles that helped you to decide.  

  1. A triangle labelled A, B, and C.

    Examine all three angles of the triangle.
    Is the measure of any of the angles greater than or equal to ?

     is greater than , so this figure is an obtuse triangle.

  1. A triangle labelled R, S, and T.

    See part (a).

    Since all the angles measure less than , the figure is an acute triangle.

  1. A triangle labelled L, M, and N.

    What does the box on angle Y mean?

    The box means that the angle at that point is a right angle.
    How can you identify this triangle?

  1. A right triangle X, Y, Z where the right angle is Y.

    See part (a).