Mathematics ACT Aspire Test 2025 – 400 Free Practice Questions to Pass the Exam

The sum of the interior angles of a triangle is a fundamental property in geometry. It is established based on the understanding that a triangle can be formed by connecting three points in a plane. Regardless of the type of triangle—whether it is scalene, isosceles, or equilateral—the total measure of the angles inside the triangle will always add up to 180 degrees.

This property can be visualized through various methods, one common method being to draw a triangle and extend one of its sides. By creating alternate interior angles, it becomes evident that the three angles indeed sum to 180 degrees.

This value is crucial in solving many geometric problems and provides the basis for various theorems and properties related to polygons. For instance, this rule extends to other polygons too, where the formula for the sum of interior angles involves the number of sides.

Thus, stating that the sum of the interior angles of a triangle is 180 degrees is accurate and essential knowledge in geometry.