Identify the geometric theorem that justifies the sum of angles in a triangle.
Check the final answer first, then review the worked steps.
Problem
Identify the geometric theorem that justifies the sum of angles in a triangle.
Step-by-step solution
Angles 1, 2, and 3 form the interior angles of a triangle. The sum of the interior angles of any triangle is always 180 degrees.
Answer
D. Triangle sum theorem