What is the sum of the angles in a triangle?

The sum of the angles in a triangle is 180 degrees. This fact is a fundamental property of triangles in Euclidean geometry. Regardless of the type of triangle—whether it is scalene, isosceles, or equilateral—the three interior angles always add up to 180 degrees.

To understand this better, imagine any triangle drawn on a flat surface. If you were to extend the lines of one of its angles outward, you can create supplementary angles on either side that visually indicate how the internal angles relate to a straight angle (which is 180 degrees). This visual approach reinforces the idea that the total must always equal 180 degrees, no matter how the triangle is shaped.

For example, in an equilateral triangle, where each angle is equal, each angle would measure 60 degrees (3 angles x 60 degrees = 180 degrees). In a right triangle, where one angle is 90 degrees, the other two angles would sum to 90 degrees, again confirming that the total is 180 degrees.

Other options present different totals that do not apply to triangles. A total of 360 degrees pertains to the sum of angles in a full circle, while 90 degrees is the measure of a right angle, and