P
5 8
Q M R
5.5 5.5
Law of Cosines (twice)
[QP^2 - QR^2 - PR^2] /[-2* QR * PR] = cos PRQ
[ 25 - 121 - 64] / [-2 * 11 *8 ] = cos PRQ = 10/11
PM^2 = MR^2 + PR^2 - 2 (MR * PR) *cos (PRQ)
PM^2 = 30.25 + 64 - 2[5.5 * 8]* (10/11)
PM ^2 =14.25
PM =sqrt [14.25] ≈ 3.77
+850 
