Part A:
- 1 and 4: Corresponding angles
- 1 and 3: Vertical angles
- 1 and 2/2 and 3/2 and 4: Supplementary angles
- 3 and 4: Alternate interior angles
Part B:
With the knowledge that m∠1 = 81°, let's use these relationships to find the rest of the angles:
- 1 and 3 are vertical: their angle measures are the same, so m∠3 = 81°
- 1 and 4 are corresponding: their angle measures are also the same, so m∠4 = 81°
- Finally, 1 and 2 are supplemental: their angle measures add up to 180°, so 81 + m∠2 = 180, making m∠2 = 99°
