In the given figure, AB||CD. If ∠APQ=70∘ and ∠PRD=120∘ then ∠QPR=?
(a)50∘
(b)60∘
(c)40∘
(d)35∘
ANSWER:
(a)50∘
AB∥CD and PQ is the transversal.
∴ ∠PQR=∠APQ=70∘ Alternate Interior Angles
Side QR of traingle PQR is produced to D.
∴ ∠PQR+∠QPR=∠PRD⇒70∘+∠QPR=120∘⇒∠QPR=50∘