What do you call a triangle that has one angle greater than 90 degrees?

• A. Acute triangle
• B. Obtuse triangle
• C. Right triangle
• D. Equilateral triangle

Answer: (B)

A triangle that has one angle greater than 90 degrees is called an obtuse triangle. This terminology is significant in geometry because it classifies triangles based on their angles. An obtuse triangle specifically contains one angle that measures more than 90 degrees, which gives it unique properties in terms of its shape and the relationships between its sides.

In contrast, an acute triangle has all angles measuring less than 90 degrees, while a right triangle has exactly one angle that measures 90 degrees. An equilateral triangle features all three angles equal to 60 degrees, which means it cannot possess an angle greater than 90 degrees. Understanding these definitions helps in identifying triangle types based on their angles, which is a fundamental concept in geometry.