Quantitative Aptitude Ques 1203

Question: In the given figure, $ AB\bot CD, $ $ AP||CD, $ $ \angle CBP=142{}^\circ . $ Find $ \angle ABP $ and $ \angle APB. $

Options:

A) $ 52{}^\circ , $ $ 38{}^\circ $

B) $ 56{}^\circ , $ $ 34{}^\circ $

C) $ 51{}^\circ , $ $ 39{}^\circ $

D) $ 57{}^\circ , $ $ 33{}^\circ $

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Answer:

Correct Answer: A

Solution:

  • $ \angle CBP+\angle PBD=180{}^\circ $ [linear pair ] $ 142{}^\circ +\angle PBD=180{}^\circ $

$ \Rightarrow $ $ \angle PBD=180{}^\circ -142{}^\circ =38{}^\circ $ Now, $ AP||CD $ and $ PB $ is the transversal. $ \angle APB=\angle PBD $ [alternate angles]

$ \Rightarrow $ $ \angle APB=38{}^\circ $ $ [\because \angle PBD=38{}^\circ ] $ $ \angle PAB+\angle ABD=180{}^\circ $ [sum of the internal angles on the same side of the transversal] $ \angle PAB+90{}^\circ =180{}^\circ $ $ [\because \angle ABD=90{}^\circ ] $

$ \Rightarrow $ $ \angle PAB=180{}^\circ -90{}^\circ =90{}^\circ $ In $ \Delta ABP, $ $ \angle ABP+\angle BPA+\angle PAB=180{}^\circ $ $ \angle ABP+38{}^\circ +90{}^\circ =180{}^\circ $

$ \Rightarrow $ $ \angle ABP=52{}^\circ $

$ \therefore $ $ \angle ABP=52{}^\circ $ and $ \angle APB=38{}^\circ $