Question

given: ∠abc ≅ ∠def and ∠ghi ≅ ∠def prove: m∠abc = m∠ghi

Explanation:

Step1: Use transitive property of congruence

If \( \angle ABC\cong\angle DEF\) and \( \angle DEF\cong\angle GHI\), then \( \angle ABC\cong\angle GHI\) (by transitive property of congruence).

Step2: Use the definition of congruent angles

If \( \angle ABC\cong\angle GHI\), then \( m\angle ABC = m\angle GHI\) (by the definition of congruent angles: congruent angles have equal measures).

Answer:

Statements	Reasons
\(5.m\angle ABC = m\angle GHI\)	\(5.\) Definition of congruent angles