Acute Triangle
Check if a triangle is acute by entering all three angles. Free online acute triangle checker verifies angle sum and determines if all angles are less than 90 degrees.
About This Calculator
An acute triangle has all three interior angles measuring less than 90 degrees. This calculator checks if three given angles form a valid triangle (sum = 180 deg) and determines if all angles are acute.
Triangle classification by angles: acute (all < 90 deg), right (one = 90 deg), or obtuse (one > 90 deg). The three angles must always sum to exactly 180 deg to form a valid triangle.
Frequently Asked Questions
What is an acute triangle?
An acute triangle is a triangle where all three interior angles are less than 90 degrees. All angles in an acute triangle are acute angles.
How do you check if a triangle is acute?
Enter all three angles. If they sum to 180 deg and each angle is less than 90 deg, the triangle is acute. If any angle equals 90 deg, it's a right triangle. If any angle exceeds 90 deg, it's obtuse.
What is the angle sum of a triangle?
The sum of all three interior angles of any triangle is always 180 degrees (pi radians). If your angles don't sum to 180 deg, they cannot form a valid triangle.
What are examples of acute triangles?
An equilateral triangle (all angles 60 deg) is acute. A triangle with angles 50 deg, 60 deg, and 70 deg is acute. A 30-60-90 triangle is right (not acute since it has a 90 deg angle).
What is the difference between acute, right, and obtuse triangles?
Acute: all angles < 90 deg. Right: exactly one 90 deg angle. Obtuse: one angle > 90 deg. A triangle can have at most one right or obtuse angle.
Is this tool free?
Yes, all calculators on Calculy are completely free to use with no registration required.