http://oi39.tinypic.com/2gxpo37.jpg
In the figure, O is the centre of the circle BCE. AB and AD are tangent to the circle at B and E respectively. AOC is a straight line and ∠CAB = 30°.
(a) Find ∠ACB.
(b) Suppose ABCD is a cyclic quadrilateral.
(i) Show that CD is tangent to circle BCE at C.
(ii) A rectangular coordinate system is introduced in the figure so that the coordinates of A and O are (0, 0) and (6, 8) respectively. Find the equation of CD.
更新1:
to 001: (a) and (b)(i) is correct, thank you! However, as said by wong, the radius should be 5 and so the b(ii) is incorrect... By the way, I still can't get the answer in b(ii). I get AC = 15, radius = 5 but I don't know what to do next...
