Angie and Becky each completed a separate proof to show that the measures of vertical angles AKG and HKB are equal. Who completed the proof incorrectly? Explain.

line AB intersecting line GH at K

Angie's Proof Statement Justification 1. Segment GH intersects segment AB at K 1. Given 2. m∠AKG + m∠GKB = 180° m∠GKB + m∠HKB = 180° 2. Definition of Supplementary Angles 3. m∠AKG + m∠ GKB = m∠GKB + m∠HKB 3. Substitution Property 4. m∠AKG = m∠HKB 4. Subtraction Property

Becky's Proof Statement Justification 1. Segment GH intersects segment AB at K 1. Given 2. m∠AKG + m∠GKB = 180° m∠GKB + m∠HKB = 180° 2. Angle Addition Postulate 3. m∠AKG + m∠ GKB = m∠GKB + m∠HKB 3. Substitution Property 4. m∠AKG = m∠HKB 4. Subtraction Property