Math Problem Statement

A surveyor 1.4m tall and 100m away from a building measures the angle of elevation of the top of a building to be 40° on a leveled ground. With the aid of a suitable sketch, find the height of the building.

Solution

To solve the problem, we will determine the height of the building using trigonometry.

Given:

  • The surveyor's height = 1.4 m
  • Distance from the building = 100 m
  • Angle of elevation = 40°

Step 1: Analyze the setup

  • The total height of the building is the sum of:

    • The height measured from the surveyor's eyes to the top of the building (denoted as hh).
    • The height of the surveyor (1.4m1.4 \, \text{m}).
  • Using the tangent function in a right triangle: tan(angle)=oppositeadjacent\tan(\text{angle}) = \frac{\text{opposite}}{\text{adjacent}} Here:

    • Opposite side = hh (distance from the surveyor's eyes to the top of the building).
    • Adjacent side = 100m100 \, \text{m}.

Step 2: Set up the equation

tan(40)=h100\tan(40^\circ) = \frac{h}{100} Solve for hh: h=100tan(40)h = 100 \cdot \tan(40^\circ)

Step 3: Calculate hh

Using tan(40)0.8391\tan(40^\circ) \approx 0.8391: h=1000.8391=83.91mh = 100 \cdot 0.8391 = 83.91 \, \text{m}

Step 4: Add the surveyor's height

The total height of the building: Total Height=h+1.4=83.91+1.4=85.31m\text{Total Height} = h + 1.4 = 83.91 + 1.4 = 85.31 \, \text{m}

Final Answer:

The height of the building is approximately 85.31 m.

Would you like me to create a sketch or explain further?


Related Questions:

  1. How does changing the angle of elevation affect the calculated height?
  2. What would happen if the surveyor was closer or farther from the building?
  3. How is trigonometry applied in real-life surveying tasks?
  4. Can the tangent function be used for angles greater than 90°? Why or why not?
  5. How would the calculation change if the ground wasn’t level?

Tip:

Always ensure that your calculator is set to the correct mode (degrees/radians) based on the angle's unit.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Angle of Elevation
Right Triangle

Formulas

tan(angle) = opposite/adjacent

Theorems

Basic Trigonometric Ratios

Suitable Grade Level

Grades 10-12