一、方位角指南或指北方向线与目标线所成的小于90°的角叫方向角.如图1,点B在点A北偏东40°方向上,而不是北偏东50°方向;点A在点B南偏西40°方向上,而不是南偏西50°方向.注意东北方向指的是北偏东45°方向.方位角问题常涉及到航海、航空等问题,由于海域(天空)宽阔,两地间的距离不易测量.当这类问题化归为解直角三角形时,首先要理解 First, the azimuth guide or the north direction of the line and the target line is formed by the angle of less than 90 ° angle.As shown in Figure 1, point B in the north east 40A point A, rather than the north east 50 ° direction ; Point A is 40 ° south west of point B instead of 50 ° south west. Note that northeast refers to the direction of 45 ° north east. Azimuth problems often involve sailing and aviation issues. Since the sea area (Sky) is wide, the distance between the two places is not easy to measure.When such problems are classified as right angle triangle, we must first understand