In quadrilateral QRTS, we have QR = 11, QS = 9, and ST=2. Sides line RQ and line ST are extended past Q and S, respectively, to meet at point P. If PS = 8 and PQ = 5, then what is RT?
Triangle PQS has all 3 sides given, so using the cosine law, we can find angle P
The use the cosine law again in triangle PRT to find RT