Two chords AB and CD of a circle with centre O intersect each other at P. If $$\angle BOC = 70^\circ$$ and $$\angle AOD = 100^\circ$$, then $$\angle APC$$ is:
$$\angle AOD = 100\degree $$
$$\angle BOC = 70\degree $$
$$\angle ACD = \angle ACP = \frac{\angle AOD}{2} = \frac{100}{2} = 50\degree$$
($$\because$$ The angle subtended at the centre is twice to that of angle subtended at the circumference by the same arc)
$$\angle BDC = \angle BAC = \frac{\angle BOC}{2} = \frac{70}{2} = 35\degree$$
In $$\triangle APC$$,
$$\angle PAC + \angle ACP + \angle APC = 180$$
$$\angle APC = 180 − 50 − 35$$
$$\angle APC = 95\degree$$
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