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Question
Find the angle between two radii at the centre of the circle as shown in the figure. Lines PA and PB are tangents to the circle at other ends of the radii and ∠APR = 140°.
Solution
\[ \Rightarrow \angle APB = 40^o\]
Also,
\[\angle\]OAP =
\[ \Rightarrow 40^o + 90^o + \angle BOA + 90^o = 360^o\]
\[ \Rightarrow \angle BOA = 140^o\]
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