You only have one side and an angle. You need side QR to determine PR and another angle. Let's say QR=x, then PR=sqrt(15.2^2+x^2-2*15.2xcos30) (cosine rule). cos30=sqrt(3)/2 so PR=sqrt(231.04+x^2-15.2xsqrt(3)).
You can use the sine rule to find angle PRQ. sinPRQ/15.2=sin30/PR; sinPRQ=7.6/PR. PRQ=arcsin(7.6/PR).