Math Problem Statement

A boat heading out to sea starts out at Point A, at a horizontal distance of 590 feet from a lighthouse/the shore. From that point, the boat’s crew measures the angle of elevation to the lighthouse’s beacon-light from that point to be 11 degrees∘. At some later time, the crew measures the angle of elevation from point B to be 2 degrees∘. Find the distance from point A to point B. Round your answer to the nearest foot if necessary.

Solution

To find the distance from point AA to point BB, we need to determine how far the boat has traveled horizontally from point AA to point BB.

Step 1: Calculate the height of the lighthouse beacon light

Given:

  • Distance from point AA to the lighthouse (shore), dA=590d_A = 590 feet
  • Angle of elevation from point AA, θA=11\theta_A = 11^\circ

Using the tangent function: tan(θA)=hdA\tan(\theta_A) = \frac{h}{d_A} where hh is the height of the lighthouse beacon light. Solving for hh: h=dAtan(θA)=590tan(11)h = d_A \cdot \tan(\theta_A) = 590 \cdot \tan(11^\circ)

Calculating hh: tan(11)0.1944\tan(11^\circ) \approx 0.1944 h=5900.1944114.696 feeth = 590 \cdot 0.1944 \approx 114.696 \text{ feet}

Step 2: Calculate the distance from point BB to the lighthouse (shore)

Given:

  • Angle of elevation from point BB, θB=2\theta_B = 2^\circ
  • Height of the lighthouse beacon light, h=114.696h = 114.696 feet

Using the tangent function again: tan(θB)=hdB\tan(\theta_B) = \frac{h}{d_B} where dBd_B is the distance from point BB to the lighthouse (shore). Solving for dBd_B: dB=htan(θB)=114.696tan(2)d_B = \frac{h}{\tan(\theta_B)} = \frac{114.696}{\tan(2^\circ)}

Calculating dBd_B: tan(2)0.0349\tan(2^\circ) \approx 0.0349 dB=114.6960.03493286.43 feetd_B = \frac{114.696}{0.0349} \approx 3286.43 \text{ feet}

Step 3: Calculate the horizontal distance from point AA to point BB

The distance from point AA to point BB is the difference between dBd_B and dAd_A: dAB=dBdA=3286.435902696.43 feetd_{AB} = d_B - d_A = 3286.43 - 590 \approx 2696.43 \text{ feet}

Rounding to the nearest foot: dAB2696 feetd_{AB} \approx 2696 \text{ feet}

Therefore, the distance from point AA to point BB is approximately 26962696 feet.

Would you like more details on any part of the solution? Here are some related questions:

  1. How is the tangent function applied in these types of problems?
  2. What are other ways to measure the height of a structure using trigonometry?
  3. Why is it important to calculate angles of elevation accurately?
  4. Can this method be applied to any distance and height measurements?
  5. What are the limitations of using tangent functions in real-life scenarios?
  6. How do errors in angle measurements affect the final distance calculation?
  7. How would this problem change if the initial distance from the lighthouse was different?
  8. What other trigonometric functions could be useful in navigation?

Tip: When dealing with trigonometric problems, always double-check your angle measurements and ensure your calculator is set to the correct unit (degrees or radians).

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Angle of elevation
Distance measurement

Formulas

Tangent function

Theorems

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Suitable Grade Level

Grades 9-12