Obtuse angle

Definition

An obtuse angle is an angle that measures more than 90 degrees but less than 180 degrees. It appears "wide" or "spread out" when compared to a right angle.

5 Must Know Facts For Your Next Test

1. 1. An obtuse angle always measures between 90 and 180 degrees.
2. 2. In a triangle, having one obtuse angle means the other two angles must be acute.
3. 3. The sum of the internal angles in any triangle is always 180 degrees.
4. 4. Obtuse angles can appear in various geometric shapes, such as obtuse triangles and certain types of polygons.
5. 5. Two obtuse angles cannot form a supplementary pair because their sum would exceed 180 degrees.

Review Questions

• 1. What is the range of degrees for an obtuse angle?
• 2. Can a triangle have more than one obtuse angle? Why or why not?
• 3. How does an obtuse angle differ from an acute and right angle?

Related terms

Acute Angle: An angle that measures less than 90 degrees and appears "sharp" or "narrow."

Right Angle: An angle that exactly measures 90 degrees, often represented by a small square in the corner.

Supplementary Angles:

Two angles that add up to exactly 180 degrees but cannot both be obtuse at the same time.