帮忙讲解图片中的题目---**Title:** 航海测量与速度计算问题 (Navigation Measurement and Speed Calculation Problem) **Problem Description:** 某海港南北方向上有两个海岸观测站A、B，距离为10海里，从港口出发的一艘轮船正沿北偏东30°方向匀速航行，某一时刻在观测站A、B两处分别测得此轮船正好航行到南偏东30°和北偏东75°方向上的C处，经过0.5时轮船航行到D处，此时在观测站A处测得轮船在北偏东75°方向上，求轮船航行的速度。(结果精确到0.1海里/时，参考数据：$\sqrt{2} \approx 1.414$, $\sqrt{3} \approx 1.732$) **Translation of Problem Description:** There are two coastal observation stations A and B located in the north-south direction of a certain seaport, with a distance of 10 nautical miles between them. A ship departing from the port sails uniformly in the direction of North-East 30°. At a certain moment, from observation stations A and B, the ship is observed to be exactly at point C, which is in the direction of South-East 30° from A and North-East 75° from B. After 0.5 hours, the ship sails to point D, at which point it is observed from station A to be in the direction of North-East 75°. Find the speed of the ship. (Round the result to 0.1 nautical miles/hour, reference data: $\sqrt{2} \approx 1.414$, $\sqrt{3} \approx 1.732$) **Reference Data:** $\sqrt{2} \approx 1.414$ $\sqrt{3} \approx 1.732$ **Diagram Description:** * **Type:** Geometric diagram representing locations and directions. * **Elements:** * **Points:** A, B, C, D. Points A and B are connected by a vertical line. * **Lines:** Lines connecting A to C, B to C, A to D, and C to D. Vertical lines indicating North direction are shown at A and C. * **Directions:** A vertical upward arrow labeled "北" (North) is shown at A and C. * **Angles:** * At A: Angle between North direction line and line AC is 30°. Angle between North direction line and line AD is 75°. The angle between the North direction line at A and the vertical line AB is 0° (since B is south of A). * At B: Angle between the North direction (which is upward from B, parallel to the North direction at A) and the line BC is 75°. * At C: Angle between North direction line and line AC is 30°. The angle between the North direction line at C and the line from C to the ship's path CD is implicitly related to the ship's sailing direction (North-East 30°). * **Relative Position:** B is south of A. C is located relative to A and B based on given angles. D is located relative to A and C based on given information. * **Labels:** Points are labeled A, B, C, D. Angles are labeled 30°, 75°, 30°, 75°. The direction "北" (North) is indicated at A and C. **Other Relevant Text:** Page number: 1