From the figure given, it can be observed that
1. Line 'l' and line 'm' are parallel lines
2. Line 'p' is a transversa perpendicula to the two parallel lines (i.e. line 'l' and line 'm')
3. ∠1 ≅ ∠2
If line p is perpendicular to linem, then, ∠4 = 90°
∠3 = ∠ 4 (Corresponding angles are equal)
Therefore, ∠3 = ∠ 4 = 90°
∠3 = 90°
If the angle at which line p and line l (i.e. ∠3 = 90°), then the relationship beween line p and line l is that they are perpendicular