Math Problem Statement

An ecologist wishes to find the height of a redwood tree that is on the other side of a creek, as shown in the figure below. From point A he finds that the angle of elevation to the top of the tree is 12.7°. He then walks 24.8 feet at a right angle from point A to point B. There he finds that the angle between AB and a line extending from B to the tree is 85.4°. What is the height h of the tree? (Round your answer to one decimal place.) h =

Incorrect: Your answer is incorrect. ft

Solution

To solve this problem, we need to use trigonometry. The scenario described involves a right triangle, and the tree's height is the vertical leg of that triangle. We are given the following information:

  1. From point A, the angle of elevation to the top of the tree is 12.712.7^\circ.
  2. From point B, the angle between the line AB and the line extending to the tree is 85.485.4^\circ.
  3. The distance between points A and B is 24.8 feet.

Step 1: Determine the distance from point B to the tree.

We first focus on triangle ABTABT, where:

  • AB=24.8AB = 24.8 feet,
  • ABT=85.4\angle ABT = 85.4^\circ, and
  • BAT=12.7\angle BAT = 12.7^\circ.

To find the distance BTBT (from point B to the tree), we can use the law of sines: ABsin(BAT)=BTsin(ABT)\frac{AB}{\sin(\angle BAT)} = \frac{BT}{\sin(\angle ABT)} Substitute the known values: 24.8sin(12.7)=BTsin(85.4)\frac{24.8}{\sin(12.7^\circ)} = \frac{BT}{\sin(85.4^\circ)} Solve for BTBT: BT=24.8sin(85.4)sin(12.7)BT = \frac{24.8 \cdot \sin(85.4^\circ)}{\sin(12.7^\circ)}

Step 2: Calculate the height of the tree.

Now that we know BTBT, we can calculate the height of the tree using the angle of elevation from point B and the tangent function. The height of the tree hh is: tan(12.7)=hBT\tan(12.7^\circ) = \frac{h}{BT} Solve for hh: h=BTtan(12.7)h = BT \cdot \tan(12.7^\circ)

Let’s calculate this step-by-step.The height of the tree is approximately 25.325.3 feet.

Would you like more details on the calculation or have any further questions? Here are 5 related questions that expand on this topic:

  1. How is the law of sines used in non-right triangles?
  2. How does the angle of elevation relate to tangent in right triangles?
  3. How can we determine the height of an object using two different points?
  4. What are the assumptions when using trigonometry in real-world applications?
  5. How would the solution change if the angles were measured in radians?

Tip: When using trigonometry, always check if your calculator is set to the correct mode (degrees or radians) based on the given angles.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Law of Sines
Angle of Elevation
Right Triangles

Formulas

Law of Sines: (AB/sin(angle BAT)) = (BT/sin(angle ABT))
Tangent function: tan(angle) = height / distance

Theorems

Law of Sines
Tangent Function

Suitable Grade Level

Grades 10-12