Triangle Angle Calculator

Find the third angle of a triangle.

Third angle (°) 70

Formula: third = 180 − angle1 − angle2

Step-by-step with your numbers:
1. Values used:
2. Angle 1 = 50 °
3. Angle 2 = 60 °
4.
5. Third angle = 70°
Did we solve your problem today?

The angles of any triangle sum to 180°.

How the Math Works

The Triangle Angle Calculator leverages the fundamental Triangle Angle Sum Theorem, which states that the sum of all three interior angles in any triangle equals 180 degrees. By inputting two known angles, the calculator subtracts their sum from 180 to determine the missing third angle. This relationship holds true for all triangles, whether they are equilateral, isosceles, or scalene, making it a universal tool for geometric problem-solving. The formula, third = 180 - angle1 - angle2, ensures precision and simplicity in calculations.

Practical Applications

This calculator is invaluable in fields like architecture, engineering, and construction, where verifying triangle measurements is critical. For instance, when designing a triangular truss or roof, knowing two angles allows engineers to confirm the third angle before finalizing the structure. It also aids in solving real-world problems such as determining unmeasured angles in land surveying or creating accurate technical diagrams. Students and educators frequently use it to validate homework or visualize geometric principles, streamlining complex problem-solving processes.

Day-to-Day Use

In everyday scenarios, this tool can assist with practical tasks like DIY projects. For example, when building a triangular shelf or garden bed, you might need to cut pieces at precise angles to ensure a perfect fit. Knowing the third angle helps avoid material waste and ensures structural stability. It also proves useful in hobbies like woodworking, model building, or even setting up sports equipment (e.g., aligning a soccer goal net). By simplifying angle calculations, it empowers individuals to tackle geometry-related tasks with confidence and accuracy.

Worked example

50° + 60° → third 70°.

FAQ

Negative result?

Then the first two angles are impossible for a triangle.