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# Triangle Sum Theorem Calculator

Sum of angles in a triangle - What is the triangle sum theoremHow do I use the triangle sum theorem calculator?Other related calculatorsFAQs

The triangle sum theorem calculator is a convenient tool to help you calculate an unknown angle value in a triangle, given two angles. Are you wondering what the triangle angle sum theorem is? Wonder no more; come along and learn how to use the triangle sum theorem to find the triangle angle you're looking for! 👩‍🏫

## Sum of angles in a triangle - What is the triangle sum theorem

According to the triangle angle sum theorem, the sum of all interior angles in a triangle equals 180°:

α + β + γ = 180°

For instance, if you wanted to determine the unknown angle α in a triangle, you would use the triangle angle sum theorem in the following way:

• α = 180° - γ - β (in degrees)
• α = π - γ - β (in radians)

You can also save time and trust the Omni triangle sum theorem calculator to do your work!

## How do I use the triangle sum theorem calculator?

Using a triangle sum theorem calculator is very straightforward! Just enter two known interior angles of a triangle in the tool. The calculator will tell you the value of a third angle according to the triangle interior angle sum theorem.

You can also change units of measurement for angles as per your convenience!

FAQs

### How do I calculate the third angle in a triangle if two other angles are 40° and 75°?

To calculate the third angle in a triangle if two other angles are 40° and 75°:

1. Add 40 to 75; in other words, sum two known interior angles of a triangle.
2. Take the sum calculated in the previous step, and subtract it from 180.
3. That's all! The value of a third angle is 66°.

### What is the sum of angles in a triangle?

According to the triangle angle sum theorem, the sum of all interior angles in a triangle equals 180°.