Definition Of Obtuse Triangle

A triangle in which one of the angles is obtuse (more than 90° and less than 180°) is known as an Obtuse Triangle.

More About Obtuse Triangle

An obtuse triangle will have one obtuse angle and two acute angles.

Example of Obtuse Triangle

â–³PQR has one obtuse angle (∠Q). So, â–³PQR is an obtuse triangle.

Video Examples: The Obtuse Triangle

Solved Example on Obtuse Triangle

Ques: How many interior angles does an octagon have?

Choices:

A. Figure1
B. Figure 3
C. Figure 2
D. None of these
Correct Answer: A

Solution:

Step 1: In Figure 1, one of the angles is more than 90° and hence Figure 1 represents an obtuse triangle.
Step 2: But Figure 2 represents acute triangle as all the angles are less than 90°
Step 3: Figure 3 represents right triangle as one of the angles is equal to 90°

Related Worksheet

• Classifying-Angles-Gr-4