Lines M and H are parallel. Find angle 3 if angle 1 = 22 ° and angle 2 = 72 °.

Let’s denote the angle by ∠4.

Since, by hypothesis, lines m and n are parallel, the angle ∠4 = ∠2 = 72 as criss-crossing angles at the intersection of parallel lines m and n secant with.

The sum of the angles ∠1, ∠3 and ∠4 is the unfolded angle, the degree measure of which is 180.

Then ∠1 + ∠3 + ∠4 = 180.

∠3 = 180 – ∠1 – ∠4 = 180 – 22 – 72 = 86.

Answer: The angle ∠3 is 86.