Ace the Officer Aptitude Rating (OAR) 2026 – Unleash Your Inner Officer!

The total interior angle sum of a triangle is 180 degrees. This fundamental property of triangles is a result of geometric principles. When you consider any triangle, regardless of the type (scalene, isosceles, or equilateral), the three interior angles will always add up to 180 degrees.

To understand why this is the case, consider that if you were to draw a line parallel to one side of the triangle through the opposite vertex, it creates alternate interior angles with the original triangle angles. The angles formed on this line, plus the angle of the triangle at the vertex, will sum to 180 degrees since they form a straight line. Since this holds true for all triangles, the conclusion about the interior angle sum being 180 degrees is consistent across all types of triangles.

Other options represent incorrect sums for a triangle's interior angles: 90 degrees is the angle sum for a right angle, 270 degrees does not correspond to any standard geometric figure, and 360 degrees is the angle sum representing a full rotation, which is applicable to quadrilaterals instead.