Question

Prove that the straight lines perpendicular to the same straight line are parallel to one
another.

Answer 1

Let  AB and CD perpendicular to the Line MN

`∠`ABD = 90°            [∵ AB  ⊥ MN ]     ......(i )

`∠`CON = 90°          [ ∵ CD ⊥ MN]      ......(ii)

Now,

`∠`ABD = `∠`CDN = 90°                    [From (i) and (ii)]

∴AB || CD, Since corresponding angles are equal.