If <1 and <2 are complementary, and <2 and < 3 are complementary, then <1 and < 3 are also complementary.
Step-by-step explanation:
Two angles are complementary when they add up to the same whole. For example, two angles are complementary when they add up to 90 degrees. This is a simple "if A=B, and B=C, then A=C" situation. The angles may have different degrees but all add up to the same one, making them complementary.
