OBTUSE ANGLE
Definition Of Obtuse Angle
Any angle greater than 90° and smaller than 180° is called an Obtuse Angle.
More About Obtuse Angle
An angle of 90° is called a right angle.
An angle of 180° is called a straight angle.
Example of Obtuse Angle
The angle shown in the figure is greater than 90° but smaller than 180°, so it is an obtuse angle.
Video Examples: Acute and Obtuse Angles in Geometry
Solved Example on Obtuse Angle
Ques: Identify the obtuse angle in the given triangle.
Choices:
A. ∠ACB
B. ∠ABC
C. ∠BAC
D. ∠CAB
Correct Answer: B
Solution:
Step 1:An angle greater than a right angle and less than a straight angle (> 90° and < 180°)="" is="" called="" an="" obtuse="">
Step 2: In the given figure, ∠A and ∠C are acute angles and ∠B is an obtuse angle.
Step 3: So, ∠ABC is an obtuse angle.
Quick Summary
- Obtuse angles are larger than right angles.
- Obtuse angles are smaller than straight angles.
- An obtuse angle measures between 90° and 180°.
🍎 Teacher Insights
Use visual aids like protractors and real-world examples to help students understand the concept of obtuse angles. Emphasize the range of values (greater than 90° and less than 180°).🎓 Prerequisites
- Angles
- Right Angles
- Straight Angles
- Angle Measurement
Check Your Knowledge
Q1: Which of the following angles is an obtuse angle?
Q2: An angle measuring 179° is:
Frequently Asked Questions
Q: What is the difference between an obtuse and an acute angle?
A: An obtuse angle is greater than 90 degrees but less than 180 degrees, while an acute angle is less than 90 degrees.
Q: Can a triangle have more than one obtuse angle?
A: No, a triangle can have at most one obtuse angle. If it had two, the sum of the angles would be greater than 180 degrees, which is not possible in Euclidean geometry.