Math Problem Statement

A boat heading out to sea starts out at Point AA, at a horizontal distance of 1465 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 13degrees∘. At some later time, the crew measures the angle of elevation from point BB to be 8degrees∘. Find the distance from point AA to point BB. Round your answer to the nearest foot if necessary.

Solution

To solve this problem, we can use trigonometry, specifically the tangent of angles, to find the height of the lighthouse and then apply the height to find the distance between points AA and BB.

Step 1: Set up known values and define variables

  1. Let hh be the height of the lighthouse.
  2. Let xx be the distance between Point AA and Point BB.
  3. The distance from the lighthouse to Point AA is 1465 feet.
  4. The angle of elevation from Point AA to the beacon is 13°.
  5. The angle of elevation from Point BB to the beacon is 8°.

Step 2: Use the tangent function to find hh

From Point AA: tan(13)=h1465\tan(13^\circ) = \frac{h}{1465} Solving for hh: h=1465tan(13)h = 1465 \cdot \tan(13^\circ)

Step 3: Calculate hh

Using tan(13)0.2309\tan(13^\circ) \approx 0.2309: h14650.2309338.06 feeth \approx 1465 \cdot 0.2309 \approx 338.06 \text{ feet}

Step 4: Use hh to find the distance xx

From Point BB, we set up a similar equation using the angle of elevation: tan(8)=h1465+x\tan(8^\circ) = \frac{h}{1465 + x} Substitute h338.06h \approx 338.06: tan(8)=338.061465+x\tan(8^\circ) = \frac{338.06}{1465 + x} Using tan(8)0.1405\tan(8^\circ) \approx 0.1405, we solve for xx: 0.1405=338.061465+x0.1405 = \frac{338.06}{1465 + x} Rearrange and solve for xx: 1465+x=338.060.14051465 + x = \frac{338.06}{0.1405} 1465+x2406.971465 + x \approx 2406.97 x2406.971465x \approx 2406.97 - 1465 x942 feetx \approx 942 \text{ feet}

Answer

The distance from Point AA to Point BB is approximately 942 feet.

Would you like a deeper explanation of any step?


Here are some related questions to explore further:

  1. How would the answer change if the angle at Point AA were 15° instead of 13°?
  2. What would be the height of the lighthouse if the boat's angle of elevation at both points was the same?
  3. How would using a different trigonometric function, such as cosine, affect our approach to this problem?
  4. What if the initial distance from the shore was given in meters? How would you convert it to feet?
  5. Could we solve this problem using the sine function instead? Why or why not?

Tip: For navigation problems like this, trigonometric functions are very effective when dealing with right-angled scenarios and elevations.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Angles of Elevation
Right Triangle Trigonometry

Formulas

tan(angle) = opposite/adjacent
tan(13°) = h / 1465
tan(8°) = h / (1465 + x)

Theorems

Tangent Function in Right Triangle

Suitable Grade Level

Grades 10-12