Respuesta :
The answer is:  [B]:  " 60° " .
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Because at whatever location,  ∠2 and ∠4 are vertical angles;
and all vertical angles have equal measurements.
Given:  m∠1  is 120°, and ∠1 is supplementary to ∠2 ;
then m∠1 + m∠2 = 180° .
So, m∠2 = (180 - 120)° = 60° .
As aforementioned:
m∠4 = m∠2 = 60° ;  which is:  Answer choice:  [B]:  " 60° " .
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Because at whatever location,  ∠2 and ∠4 are vertical angles;
and all vertical angles have equal measurements.
Given:  m∠1  is 120°, and ∠1 is supplementary to ∠2 ;
then m∠1 + m∠2 = 180° .
So, m∠2 = (180 - 120)° = 60° .
As aforementioned:
m∠4 = m∠2 = 60° ;  which is:  Answer choice:  [B]:  " 60° " .
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