In lat longs, Angle = (Math.Atan2(Pa.Lat_origin,Pa.Lng_origin))*180/Math.PI may not be an appropriate equation, but if that's what Angle is, then
Pa.Lat_origin = distance*sin(Angle*Math.PI/180)
Pa.Lng_origin = distance*cos(Angle*Math.PI/180)
also holds, where
distance = sqrt(Pa.Lat_origin*Pa.Lat_origin+Pa.Lng_origin*Pa.Lng_origin)
y = sin(angle)*distance
x = cos(angle)*distance