73. As noted in Exercise $1.33$, a spelunker is surveying a cave. She follows a passage 180m straight west, then 210m in a direction 45° east of south, and then 280m at 30° east of north. After a fourth unmeasured displacement she finds herself back where she started.

 73. As noted in Exercise $1.33$, a spelunker is surveying a cave. She follows a passage 180m straight west, then 210m in a direction 45° east of south, and then 280m at 30° east of north. After a fourth unmeasured displacement she finds herself back where she started. Use the method of components to determine the magnitude and direction of the fourth displacement. Draw the vector addition diagram and show that it is in qualitative agreement with your numerical solution.