In a cyclic quadrilateral, given 3 sides and included angle between two of these sides, how to find fourth side?

Given 3 sides and angle included between 2 sides how to find fourth side of cyclic quadrilateral
PQ=a	2
QR=b	3	Radians	Cos	Sin
Angle PQR	135	2.356194	-0.70711	0.707107
RS=c	4	RS can not be greater than 2R
Find PR by cosine rule	21.48528	4.635222
2R = PR / Sin (angle PQR)	6.555194	So R=	3.277597
Find angle ROS by (1/2*RS)/R= Sin (1/2*Angle ROS)	0.610203	0.656317	37.6042	0.656317	0.792245	0.610203
1/2*Angle ROS=Angle RPS	37.6042
AngleRSP= 180 deg- Angle PQR	(Reason- Oppo. Angle of cyclic quad. Are supplementary						45	82.6042	97.3958	97.3958
Find angle SRP by anglesum property of triangle	97.3958	1.699877		0.991681
Angle SOR = 2 x Angle SRP
1/2*SP/R= Sin(Angle SRP)
Thus SP can be found, in otherwordsSP can befoundby Sine Rule	SP=	6.500658
Remember the constant of sine rule is 2xR