A plane flying a straight course observes a mountain at a bearing of 30.2 to the right of its course. At that time the plane is 9 kilometers from the mountain. A short time later, the bearing to the mountain becomes 40.2. How far is the plane from the mountain when the second bearing is taken (to the nearest tenth of a km)? 7 km 13.1 km 4.7 km 11.5 km