Assessment and Learning in Knowledge Spaces (ALEKS) Basic Math Placement Practice Test

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

This property can be understood through various methods, such as geometric proofs involving parallel lines or by dividing the triangle into smaller components and analyzing the angles formed. For example, if you draw a horizontal line through one vertex of the triangle parallel to the opposite side, the alternate interior angles created by the transversal will correspond to the triangle's angles, demonstrating that their sum equals 180 degrees.

This consistent total for the angles is a crucial principle in geometry, serving as a foundation for more complex concepts and calculations involving triangles.