🔍 Key Concepts

• Relative bearings (e.g., “9° on your starboard bow”) and what “abeam” means (90° from the bow) • Right triangle geometry: the line of sight to the light forms the hypotenuse, and the distance off when abeam is the side opposite the initial bearing angle • Using sine of a small angle to find the opposite side of a right triangle when you know the hypotenuse

💭 Think About

• Sketch the situation as a right triangle: your track is one side, the line to the light is another, and the distance off when abeam is a perpendicular distance. Which side of the triangle is 21 miles? • How does the initial 9° relative bearing relate to the angle in your right triangle? Is it the angle between your course line and the line of sight to the light? • Once you identify the correct trigonometric function, plug in 21 miles and 9°. Which answer choice is closest to that result?

✅ Before You Answer

• Confirm that “abeam” means the light is exactly 90° from your heading (on the beam) • Make sure you are using sine for opposite/hypotenuse, not cosine or tangent, if that matches your triangle setup • After calculating, check if the result is reasonable: a small angle like 9° should give a distance off that is much less than 21 miles, but not extremely tiny