Maths HKCEE 2000 #16

16. In Figure 9, C is the centre of the circle PQS . OR and OP are tangent to the circle at S and P respectively. OCQ is a straight line and ∠QOP = 30° .

(b) Suppose OPQR is a cyclic quadrilateral.

(ii) A rectangular coordinate system is introduced in Figure 9 so that the coordinates of O and C are (0, 0) and (6, 8) respectively. Find the equation of QR .

請問第Bii怎樣solve?thx
答案:3x+4y-75=0

圖形:http://upload.lsforum.net/users/public/q38889figure%209c238.jpg