Three straight lines intersect at one point Find angle 1 if angle 2+ angle 3 = 142 degrees

When three straight lines intersect, 6 angles are formed (clockwise ∠1, ∠2, ∠3, ∠4, ∠5 and ∠6), the sum of which is 360 °. In this case, the sum of ∠1, ∠2, ∠3 and ∠4, ∠5, ∠6 is equal to 360 ° / 2 (since the sum of these angles makes up the unfolded angle). Thus:
∠1 + ∠2 + ∠3 = 360 ° / 2.
Since ∠2 + ∠3 = 142 °, then:
∠1 + 142 ° = 180 °.
Let’s solve a linear equation with one variable:
∠1 = 180 ° – 142 °;
∠1 = 38 °.
Answer: the degree measure ∠1 is 38 °.