Since PC and QC = 1, then PQ = sqrt (2)
Let A = (0,,0) and P = (4,5) so AP =sqrt [ 4^2 + 5^2] = sqrt (41) = AQ
So....by Law of Cosines
PQ^2 = AP^2 + AQ^2 -2 (AP)(AQ) cos (PAQ)
2 = 41 + 41 - 2 (sqrt 41)( sqrt 41) cos (PAQ)
-80 / (- 2 * 41 ) = cos PAQ
80 /82 = 40/41 cos PAQ
sin PAQ = sqrt [ 1 - (40/41)^2 ] = sqrt [ 41^2 - 40^2] / 41 = sqrt (81) / 41 = 9 / 41
CORRECTED ANSWER !!!!