Math Problem Statement

A woman standing on a hill sees a flagpole that she knows is 55 ft tall. The angle of depression to the bottom of the pole is 14°, and the angle of elevation to the top of the pole is 18°. Find her distance x from the pole. (Round your answer to one decimal place.)

Solution

This problem involves using trigonometry to find the distance from the woman to the flagpole, denoted as xx. We'll be using the angles of depression and elevation, along with the height of the flagpole, to set up our equations.

Step 1: Break the problem into two triangles

  1. Triangle 1: Involving the angle of depression to the bottom of the pole.

    • The angle of depression is 1414^\circ.
    • Let the horizontal distance between the woman and the base of the flagpole be xx.
    • The height from the woman's eye level to the base of the pole is unknown (denote this height as h1h_1).
  2. Triangle 2: Involving the angle of elevation to the top of the pole.

    • The angle of elevation is 1818^\circ.
    • The total height of the flagpole is 55 feet, so the height from the woman’s eye level to the top of the pole will be 55h155 - h_1.

Step 2: Set up trigonometric equations

We will use the tangent function because it relates angles to the ratio of the opposite side over the adjacent side.

  • For Triangle 1 (angle of depression): tan(14)=h1x\tan(14^\circ) = \frac{h_1}{x} Therefore: h1=xtan(14)h_1 = x \cdot \tan(14^\circ)

  • For Triangle 2 (angle of elevation): tan(18)=55h1x\tan(18^\circ) = \frac{55 - h_1}{x} Therefore: 55h1=xtan(18)55 - h_1 = x \cdot \tan(18^\circ)

Step 3: Solve the system of equations

Substitute h1=xtan(14)h_1 = x \cdot \tan(14^\circ) into the second equation: 55(xtan(14))=xtan(18)55 - (x \cdot \tan(14^\circ)) = x \cdot \tan(18^\circ) Simplify and solve for xx: 55=x(tan(18)+tan(14))55 = x \cdot (\tan(18^\circ) + \tan(14^\circ)) x=55tan(18)+tan(14)x = \frac{55}{\tan(18^\circ) + \tan(14^\circ)}

Now, we can calculate xx using the tangent values of 1818^\circ and 1414^\circ.

tan(18)0.3249,tan(14)0.2493\tan(18^\circ) \approx 0.3249, \quad \tan(14^\circ) \approx 0.2493 x=550.3249+0.2493=550.5742x = \frac{55}{0.3249 + 0.2493} = \frac{55}{0.5742} x95.8ftx \approx 95.8 \, \text{ft}

Final Answer:

The woman is approximately 95.8 feet away from the flagpole.

Would you like further details or clarifications?


Here are 5 related questions you might find helpful:

  1. How would the solution change if the flagpole were 70 feet tall?
  2. What if the angle of elevation were larger, say 25°?
  3. How can the distance be calculated if only one angle is given?
  4. Can the method be applied if the observer is standing on a flat surface?
  5. How do the angles of elevation and depression affect the height of the triangles?

Tip: Always ensure your calculator is set to degrees when dealing with angle problems in trigonometry.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Angles of Elevation and Depression
Tangent Function

Formulas

tan(θ) = opposite / adjacent
h1 = x * tan(14°)
55 - h1 = x * tan(18°)
x = 55 / (tan(18°) + tan(14°))

Theorems

Tangent function in right-angle triangles

Suitable Grade Level

Grades 10-12