Part A: 1 and 4 are corresponding angles. 3 and 4 are alternate interior angles. 1 and 2 are supplementary angles. I don't know how many relationships you need, so I will put these 3 for now, but these relationships can help you solve part B.
Part B: By the corresponding angles postulate, 1 and 4 are equal, so m∠4 = 81°. By Alternate Interior Angles Theorem, 4 and 3 are equal, so m∠3 = 81°. Since 1 and 2 are supplementary angles, they add up to 180°. m∠1+m∠2=180°⇒ 81°+m∠2=180°⇒m∠2=99°.
