2. A small plane is at a point P, which is 2600 feet directly above an observer on the ground at point O. The plane then flies 4500 feet to a point Q, where the line between the observer and the plane makes a 50 angle with the vertical. a) What is the distance between the observer and Q? b) How much elevation did the plane gain between P and Q? 3. An observer standing on the southern bank of a river sees a tree that is much more than 100 feet downstream on the northern bank of the river. The angle formed by the southern bank and the line from the observer to the tree is 15. After walking 100 feet downstream, the observer measures the angle formed by the southern bank and the line to the same tree to be 25. Find the width of the river.