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