An obtuse angle's measure is:A.exactly 90.B.between 90 and 180.C.between 0 and 90.

Identifying the Characteristics of an Obtuse Angle

1. Definition: An obtuse angle is defined as any angle that measures greater than 90 degrees but less than 180 degrees.

2. Analysis of Options:

   • Option A (exactly 90): This describes a right angle, not an obtuse angle.
   • Option B (between 90 and 180): This fits the definition of an obtuse angle.
   • Option C (between 0 and 90): This describes an acute angle, not an obtuse angle.

Final Conclusion

The correct answer is B. between 90 and 180. An obtuse angle is characterized by its measure being greater than 90 degrees and less than 180 degrees.