Question

two plane mirror PQ and Rs are parallel to each other a b shazzy mirror PQ and be reflected ray moves along the path BCCI se mera RS rate and again reflect back long CD prove that AB is parallel to CD

Answer 1

At point B, draw BE ⊥ PQ and at point C, draw

CF ⊥ RS.

∠1 = ∠2 …(i)

(Angle of incidence is equal to angle of reflection)

∠3 = ∠4 …(ii) [Same reason]

Also, ∠2 = ∠3 ... (iii) [Alternate angles]

⇒ ∠1 = ∠4 [From (i), (ii), and (iii)]

⇒ 2∠1 = 2∠4

⇒ ∠1 + ∠1 = ∠4 + ∠4

⇒ ∠1 + ∠2 = ∠3 + ∠4 [From (i) and (ii)]

⇒ ∠BCD = ∠ABC Hence, AB || CD. [Alternate angles are equal] Proved.