Let us prove that angle 1 is complementary to angle 3 step by step.
1. We have been given that angle 1 is complementary to angle 2.
2. Since we know that complementary angles add up to 90 degrees, therefore, by the definition of complementary .
3. We have been also given that line segment BD bisects .
4. By the definition of bisect .
5. Angles are congruent if their measures, in degrees, are equal, therefore, by angle congruence postulate .
6.
Upon substituting in above equation we will get,
Therefore, by substitution property of equality .
Hence, proven that angle 1 is complementary to angle 3.