Math Problem Statement

Salem is standing at the bottom of a tall building and looking up at the top of the building. He measures the angle of elevation to the top of the building to be 30°. If Salem is 50 m away from the base of the building, how tall is the building?

Solution

The problem involves finding the height of a building using trigonometry. Let’s break it down step by step:

  1. Given Information:

    • The angle of elevation: 3030^\circ
    • The distance from Salem to the base of the building (adjacent side): 50m50 \, \text{m}
    • We need to find the height of the building (xx).
  2. Trigonometric Relationship: From the image, it is clear that the problem involves a right triangle where:

    • The height of the building (xx) is the opposite side.
    • The distance from Salem to the base of the building (50m50 \, \text{m}) is the adjacent side.
    • The tangent function is defined as: tan(θ)=oppositeadjacent\tan(\theta) = \frac{\text{opposite}}{\text{adjacent}} So, in this case: tan(30)=x50\tan(30^\circ) = \frac{x}{50}
  3. Solve for xx: Multiply both sides of the equation by 5050: x=50tan(30)x = 50 \cdot \tan(30^\circ)

  4. Substitute the Value of tan(30)\tan(30^\circ): From trigonometric tables: tan(30)=330.577\tan(30^\circ) = \frac{\sqrt{3}}{3} \approx 0.577 Substituting this value: x=500.577=28.85mx = 50 \cdot 0.577 = 28.85 \, \text{m}

Correct Answer:

The height of the building is approximately 28.85 meters.

Dropdown Selection:

From the options visible in the image, the correct expression to choose is: x=50tan30x = 50 \tan 30^\circ


Do you have any questions or need further clarifications?

Related Questions:

  1. What is the value of tan(45)\tan(45^\circ), and how does it apply in similar problems?
  2. How would the solution change if the angle of elevation was 4545^\circ?
  3. How can we verify the answer using the sine rule instead of tangent?
  4. Why is tan(θ)\tan(\theta) preferred here instead of sin(θ)\sin(\theta) or cos(θ)\cos(\theta)?
  5. What is the general relationship between the angle of elevation and the height of the building as distance changes?

Tip:

Always check if the correct trigonometric function (sine, cosine, or tangent) applies based on the given sides of the triangle!

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Angles of Elevation
Tangent Function

Formulas

tan(θ) = opposite/adjacent

Theorems

Trigonometric Ratios in Right-Angled Triangles

Suitable Grade Level

Grade 8-10