Select the statement that is missing from the proof below showing that vertical angles formed by intersecting lines are congruent. Statements Reasons
1. ∠ABD and ∠ABC form a linear pair,∠CBE and ∠ABC form a linear pair 1. Definition of a linear pair
2. ∠ABD and ∠ABC are supplementary,∠CBE and ∠ABC are supplementary 2. Linear pair postulate
3. m∠ABD + m∠ABC = 180°,m∠CBE + m∠ABC = 180° 3. Definition of supplementary
4. ? 4. Substitution Property of Equality
5. m∠ABD = m∠CBE 5. Subtraction Property of Equality
6. ∠ABD≅∠CBE 6. Definition of congruent angles

m∠ABD+ m∠ABC = m∠DBC

m∠ABD+m∠DBE = m∠ABE

m∠ABD+m∠ABC=m∠DBE+m∠EBC

m∠ABD+ m∠ABC = m∠CBE + m∠ABC