Quantitative Aptitude Ques 1527
Question: Two chords AB and CD of a circle with centre O, intersect each other at P. If $ \angle AOD=100{}^\circ $ and $ \angle BOC=70{}^\circ , $ then the value of $ \angle APC $ is
Options:
A) $ 80{}^\circ $
B) $ 75{}^\circ $
C) $ 85{}^\circ $
D) $ 95{}^\circ $
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Answer:
Correct Answer: D
Solution:
- (d) In the given figure,
$ \angle AOD=100{}^\circ $
$ \Rightarrow $ $ \angle BOC=70{}^\circ $
Now, join AC.
$ \angle ACD=\frac{1}{2}\angle AOD $
[since, angle subtended at the centre is twice the angle subtended on circumference of following circle]
$ =\frac{1}{2}\times 100=50{}^\circ $
Similarly, $ \angle CAB=\frac{1}{2}\times \angle DOB=\frac{1}{2}\times 70{}^\circ =35{}^\circ $
In $ \Delta APC, $ $ \angle APC=180{}^\circ -\angle ACP-\angle CAB $
$ =180{}^\circ -50{}^\circ -35{}^\circ $ $ [\because \angle ACP=\angle ACD] $ $ =95{}^\circ $