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

The sum of the interior angles of a triangle is 180 degrees. This is a fundamental property of triangles in Euclidean geometry. To understand why, consider that a triangle can be divided into two right triangles by drawing a line from one vertex to the opposite side. Each right triangle has two angles that sum to 90 degrees. Since there are three angles in the original triangle and you can relate it to these two right angles, the total sum becomes 90 degrees + 90 degrees = 180 degrees. This property applies to all types of triangles, regardless of their shape. Understanding this concept is essential for solving various geometrical problems and for advancing in topics that involve polygon properties.