Daniel is constructing a fence that consists of parallel sides line AB and line EF. Complete the proof to explain how he can show that m∠GKB = 120° by filling in the missing justifications. StatementJustification
line AB ∥ line EF
m∠ELJ = 120°Given
m∠ELJ + m∠ELK = 180°Linear Pair Postulate
m∠BKL + m∠GKB = 180°Linear Pair Postulate
m∠ELJ + m∠ELK = m∠BKL + m∠GKBTransitive Property
∠ELK ≅ ∠BKL1.
m∠ELK = m∠BKL2.
m∠ELJ + m∠ELK = m∠ELK + m∠GKBSubstitution Property
m∠ELJ = m∠GKBSubtraction Property
m∠GKB = m∠ELJSymmetric Property
m∠GKB = 120°Substitution

1. Alternate Interior Angles Theorem; 2. Definition of Congruence
1. Alternate Exterior Angles Theorem; 2. Substitution Property
1. Definition of Congruence; 2. Alternate Interior Angles Theorem
1. Substitution Property; 2. Alternate Exterior Angles Theorem