#### Answer

α and β are complementary angles.

#### Work Step by Step

In given figure 22,
producing the line DC along vertical post to meet the horizontal at "B"- a right triangle ABC, right angled at B is formed as vertical posts are perpendicular to the horizontal-
In right triangle ABC-
$ \angle A$ = α (Given)
$ \angle C$ = β
( Vertically opposite angles are same at intersection of two lines )
Therefore-
α + β = $90^{\circ}$
(Sum of acute angles of a right triangle is always $90^{\circ}$
Hence α and β are complementary angles.