Math Problem Statement

Two docks are located on an east-west line 2586 ft apart. From dock A, the bearing coral reef is 63°28'. From dock B, the bearing of the coral reef is 333°28'. Find the distance from dock A to the coral reef.

Solution

The problem describes two docks located on an east-west line, with bearings of a coral reef given from each dock. The goal is to find the distance from Dock A to the coral reef.

We can approach this problem using the law of sines in trigonometry. The two docks, Dock A and Dock B, and the coral reef form a triangle. The distance between the two docks, ABAB, is 2586 ft. The bearings of the coral reef from both docks are given, allowing us to find the interior angles of the triangle.

Step 1: Find the angle at the coral reef

The bearings are relative to the north direction:

  • From Dock A, the bearing to the coral reef is 632863^\circ28'.
  • From Dock B, the bearing to the coral reef is 33328333^\circ28'.

Since the bearing from Dock B is measured clockwise from north, the angle between Dock A and Dock B at the coral reef can be calculated as the difference between the bearings: θ=333286328=270.\theta = 333^\circ28' - 63^\circ28' = 270^\circ. Thus, the angle at the coral reef is θ=270\theta = 270^\circ, which is equivalent to 9090^\circ, as this is the difference in the bearings.

Step 2: Find the interior angles of the triangle

  • The angle at Dock A is the bearing measured clockwise from the north (east is 90°), so: A=906328=2632.\angle A = 90^\circ - 63^\circ28' = 26^\circ32'.
  • The angle at Dock B is: B=33328270=6328.\angle B = 333^\circ28' - 270^\circ = 63^\circ28'.

The three angles in the triangle sum to 180180^\circ, so the angle at the coral reef CC can be found as: C=180AB.\angle C = 180^\circ - \angle A - \angle B. Substituting the values: C=18026326328=90.\angle C = 180^\circ - 26^\circ32' - 63^\circ28' = 90^\circ. This means the triangle is a right triangle.

Step 3: Apply the Law of Sines

The Law of Sines states: asinA=bsinB=csinC,\frac{a}{\sin A} = \frac{b}{\sin B} = \frac{c}{\sin C}, where aa, bb, and cc are the sides opposite angles AA, BB, and CC, respectively.

Since CC is 9090^\circ, we know that c=AB=2586 ftc = AB = 2586 \text{ ft}. To find the distance from Dock A to the coral reef (side bb), we use: bsinB=csinC.\frac{b}{\sin B} = \frac{c}{\sin C}. Substituting the known values: bsin6328=2586sin90.\frac{b}{\sin 63^\circ28'} = \frac{2586}{\sin 90^\circ}. Since sin90=1\sin 90^\circ = 1, this simplifies to: b=2586×sin6328.b = 2586 \times \sin 63^\circ28'.

Step 4: Calculate the distance

Now, let's compute bb, the distance from Dock A to the coral reef.

b=2586×sin(6328).b = 2586 \times \sin(63^\circ28').

I'll calculate that now.The distance from Dock A to the coral reef is approximately 2313.63ft2313.63 \, \text{ft}.

Would you like more details, or do you have any further questions?

Here are 5 related questions to consider:

  1. How would the solution change if the bearing from Dock B were different?
  2. How does the Law of Sines help in solving non-right triangles?
  3. Can you derive the formula for bearings between two points using trigonometry?
  4. What if the distance between the two docks was given in meters instead of feet?
  5. How would you find the distance from Dock B to the coral reef?

Tip: In bearing problems, always ensure you interpret angles correctly relative to the north direction when converting them for trigonometric use.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Bearings
Right Triangles

Formulas

Law of Sines: (a/sinA) = (b/sinB) = (c/sinC)
Bearing calculation: θ = (bearing from B) - (bearing from A)
Right triangle property: sum of angles = 180°

Theorems

Law of Sines
Triangle Angle Sum Theorem

Suitable Grade Level

High School (Grades 10-12)