Two bird nests, 3.6 m and 6.1 m high, are on trees across a pond from each other, at points P and Q. The distance between the nests is too wide to measure directly (and there is a pond between the trees). A birdwatcher at point R can sight each nest along a dry path. RP = 16.7 m and RQ = 27.4 m. QPR is a right angle. What is the distance d between the nests?​