An observer (O) spots a plane (P) taking off from a local airport and flying at a [tex]$33^{\circ}$[/tex] angle horizontal to her line of sight and located directly above a tower (T). The observer also notices a bird (B) circling directly above. If the distance from the plane (P) to the tower (T) is 7,000 feet, how far is the bird (B) from the plane (P)? Round to the nearest whole number.

A. 3,815 feet
B. 5,873 feet
C. 8,343 feet
D. 10,779 feet



Answer :

Let's solve the problem step by step.

### Step 1: Understanding the Problem
- We have a plane (P) taking off at a 33-degree angle relative to the observer (O)'s line of sight.
- The plane (P) is directly above a tower (T).
- The distance from the plane (P) to the tower (T) is 7,000 feet.
- We need to find the horizontal distance from the bird (B) circling at a point directly above the observer (O) to the plane (P).

### Step 2: Determining the Relevant Triangle
- We have a right triangle where:
- The angle at the observer's line of sight (O) is [tex]\(33^\circ\)[/tex].
- The distance from the plane (P) to the tower (T) is the adjacent side of the triangle, which is 7,000 feet.
- The distance we need to find, from the bird (B) to the plane (P), is the opposite side of the triangle.

### Step 3: Using Trigonometry
- To determine the distance from the bird to the plane, we use the tangent function, which relates the opposite side to the adjacent side in a right triangle:
[tex]\[ \tan(\text{angle}) = \frac{\text{opposite}}{\text{adjacent}} \][/tex]
Here, we need to find the opposite side (distance from bird to plane), and we know the angle and the adjacent side (7,000 feet).

### Step 4: Calculation
1. Convert the angle from degrees to radians:
[tex]\[ \text{angle in radians} = 33^\circ \times \left(\frac{\pi}{180}\right) = 0.57596 \text{ radians} \quad (\text{approximately}) \][/tex]

2. Use the tangent function:
[tex]\[ \tan(33^\circ) = \tan(0.57596 \text{ radians}) \][/tex]
So,
[tex]\[ \frac{\text{opposite}}{7000} = \tan(33^\circ) \][/tex]
From this, we can solve for the opposite side:
[tex]\[ \text{opposite} = 7000 \times \tan(33^\circ) \][/tex]

3. Using the value from the tangent function:
[tex]\[ \text{opposite} = 7000 \times \tan(33^\circ) \approx 10779.054746702079 \][/tex]

4. Round the result to the nearest whole number:
[tex]\[ \text{distance from bird to plane} \approx 10779 \text{ feet} \][/tex]

### Conclusion
The distance from the bird (B) to the plane (P) rounded to the nearest whole number is 10,779 feet.