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

The total of the interior angles of a triangle is always 180 degrees. This is a fundamental property of triangles in Euclidean geometry, which is the geometry most commonly taught in elementary education.

To understand why this is the case, consider that a triangle can be formed by drawing three straight lines that meet at three points, which are called vertices. When the three angles of this triangle are added together, they will always sum to 180 degrees, regardless of the type of triangle—whether it is scalene, isosceles, or equilateral.

This property can also be visualized through various methods, such as drawing parallel lines and transversals or by dividing a triangle into smaller shapes whose angle measures are easier to calculate. Each of these methods reaffirms that the sum of the angles within any triangle will total 180 degrees.

The other options do not represent the correct sum of the interior angles for any triangle. For instance, 90 degrees would apply to a right angle, while 270 degrees and 360 degrees pertain to larger geometric figures, such as quadrilaterals or full circles. Understanding the sum of a triangle's interior angles is a crucial concept in geometry and foundational for further study in mathematics.