The Total solution for NCERT class 6-12
If two straightlines are perpendicular to the same line, prove that they are parallel to eachother.
Let lines l and m are perpendicular to n, then
∠1= ∠2=90°
Since, lines l and m cut by a transversal line n and thecorresponding angles are equal, which shows that, line l is parallel to line m.