急! F4 Properties Circles 11q10

do u have the ans of q30?
i am not sure whether my ans is correct or not..

2012-05-19 21:48:17 補充：
28-29
http://i615.photobucket.com/albums/tt234/chandaiman199111/11.jpg
http://i615.photobucket.com/albums/tt234/chandaiman199111/12.jpg
http://i615.photobucket.com/albums/tt234/chandaiman199111/13-2.jpg
http://i615.photobucket.com/albums/tt234/chandaiman199111/14-2.jpg


2012-05-20 10:07:26 補充：
(i guess) 0<90

2012-05-20 10:08:07 補充：
0 smaller than theta smaller than 90
sorry,i can't type out the symbol

2012-05-20 10:30:15 補充：
first
PRS = 90 (angles in semicircle)
but theta cannot be 90,
if theta = 90,
angle PRO = 0
so angle RPQ = 0 (alt angles,OR//PQ)
it is impossible because OR//PQ.
theta must be positive.
Therefore,0 smaller than theta smaller than 90
(i just guess,not sure)

2012-05-20 10:41:01 補充：
typo,should be (angle in semicircle)