What is the sum of the internal angles of a triangle?

The sum of the internal angles of a triangle is always 180 degrees. This is a fundamental property of Euclidean geometry and can be visualized by drawing a triangle and extending one of its sides. When you do this, it becomes clear that the angles inside the triangle add up to form a straight line, which measures 180 degrees.

This property holds true regardless of the type of triangle—whether it is acute, obtuse, or right. Each triangle, no matter the shape or size, adheres to this rule. Understanding this principle is vital in various fields of mathematics, geometry, and even in applications such as architectural design and engineering, where the properties of triangles are frequently utilized.

The other options reflect different types of angle sums unrelated to triangles, which can lead to confusion if one is not familiar with basic geometric principles. However, the definitive answer for the sum of a triangle's internal angles is indeed 180 degrees.