Question

Two parallel lines are crossed by a transversal. If measure of angle 6 is 123.5 then measure of angle 1 is.....

Answer 1

The picture in the attached figure

we know that
m ∠ 6=123.5°

m ∠6+m∠2=180°-------> by supplementary angles
so
m∠2=180-m∠6-----> 180-123.5------> m∠2=56.5°

m∠1=m∠2--------> by corresponding angles
so
m∠1=56.5°

the answer is
m∠1 is 56.5°