Let's label the given angles and identify which one can be helpful in finding the measure of ∠1.
Angles ∠1 and ∠6 form a linear pair, so their measures add to 180^(∘).
m∠1+m∠6=180^(∘)
It is given that m∠6=125^(∘). We can substitute this in the equation above to find the measure of ∠1.
