What is the sum of the angles in a triangle?

• A. 90°
• B. 180°
• C. 270°
• D. 360°

Answer: (B)

The sum of the angles in any triangle is always 180 degrees. This principle comes from the basic properties of triangles, which state that when you add the measures of all three interior angles together, they equal 180°. This is true for all types of triangles, whether they are scalene, isosceles, or equilateral.

This fundamental property of triangles is used frequently in geometry to solve problems related to interior angles and can also be applied to find missing angle measures when two angles are known. For instance, if two angles in a triangle measure 50 degrees and 70 degrees, one can easily determine the measure of the third angle by subtracting the sum of the known angles from 180 degrees, leading to a logical solution.

Understanding that 180 degrees is the total for the angles in a triangle helps in various geometric proofs and calculations, reinforcing the importance of this concept in broader mathematical studies.