Obtuse Triangle Calculator
Determine if your triangle is obtuse and calculate its properties
Calculate Obtuse Triangle
Example Calculations
Obtuse Triangle Example
Given: Angles A = 30°, B = 40°, C = 110°
Analysis: Angle C (110°) > 90°
Result: This is an Obtuse Triangle
Acute Triangle Example
Given: Angles A = 60°, B = 70°, C = 50°
Analysis: All angles < 90°
Result: This is an Acute Triangle
Right Triangle Example
Given: Angles A = 30°, B = 60°, C = 90°
Analysis: Angle C = 90°
Result: This is a Right Triangle
Triangle Types
Obtuse Triangle
One angle > 90°
The largest angle is obtuse
Right Triangle
One angle = 90°
Has a right angle
Acute Triangle
All angles < 90°
All angles are acute
Key Properties
Obtuse Angle
Exactly one angle > 90°
Acute Angles
Two angles < 90°
Longest Side
Opposite to obtuse angle
Area Formulas
Same as any triangle
Understanding Obtuse Triangles
What is an Obtuse Triangle?
An obtuse triangle is a triangle that has exactly one angle greater than 90 degrees. This large angle is called the obtuse angle, while the other two angles are acute (less than 90 degrees).
How to Identify
- •Check if any angle > 90°
- •Sum of all angles must equal 180°
- •Use Law of Cosines for sides
- •Longest side opposite obtuse angle
Area Calculation Methods
Base × Height
Area = ½ × base × height
Heron's Formula
Area = √[s(s-a)(s-b)(s-c)]
SAS Formula
Area = ½ × a × b × sin(C)
Note: Obtuse triangles follow the same area formulas as acute and right triangles.