The horizontal angles from the boat between A and B and B and C, the stations on the shore are respectively θ1 and θ2. The distances AB = L1 and BC = L2. For calculating the angle α2 at C between the boat and station B is obtained by using the following formula: where (β is horizontal angle between A and C at B).

The horizontal angles from the boat between A and B and B and C, the s

1.	The horizontal angles from the boat between A and B and B and C, the stations on the shore are respectively θ1 and θ2. The distances AB = L1 and BC = L2. For calculating the angle α2 at C between the boat and station B is obtained by using the following formula: where (β is horizontal angle between A and C at B).
A.	A
B.	B
C.	C
D.	D
Answer» E.