Answer:
Step-by-step explanation:
1). Since, m∠1 + m∠2 = 180° [Supplementary angles]
If m∠2 = 120°
m∠1 + 120° = 180°
m∠1 = 180° - 120°
m∠1 = 60°
2). If a transversal intersects two parallel lines on the top and middle,
∠1 and ∠5 will be corresponding angles.
3). Since, m∠1 = m∠5 = 60° (Corresponding angles)
Therefore, both the lines on top and middle will be parallel.
4). Since, m∠9 + m∠11 = 180° [Supplementary angles]
If m∠11 = 120°
m∠9 + 120° = 180°
m∠9 = 60°
Since, m∠1 = m∠9 = 60° [Corresponding angles]
Therefore, both the lines on the top and bottom shelves will be parallel.
5). Since, m∠5 = m∠9 = 60° [Corresponding angles]
Therefore, middle and bottom shelves will be parallel.
