Math Problem Statement

When the angle of elevation of the sun is 60° 12', the length of the shadow of a building on a level plane is 45.3 ft. What is the height of the building

Solution

To find the height of the building, we can apply trigonometric principles. Specifically, we use the tangent of the angle of elevation. The relationship between the angle of elevation θ\theta, the height of the building hh, and the length of the shadow LL is given by:

tan(θ)=hL\tan(\theta) = \frac{h}{L}

Where:

  • θ=6012\theta = 60^\circ 12' (angle of elevation),
  • L=45.3L = 45.3 ft (length of the shadow),
  • hh is the height of the building, which we need to find.

Step 1: Convert the angle to decimal form.

The angle of elevation is 601260^\circ 12', where 1212' (minutes) needs to be converted to degrees. Since 1 minute = 160\frac{1}{60} degree, we have:

6012=60+1260=60+0.2=60.260^\circ 12' = 60^\circ + \frac{12}{60} = 60^\circ + 0.2^\circ = 60.2^\circ

Step 2: Use the tangent function.

Now we use the tangent function:

tan(60.2)=h45.3\tan(60.2^\circ) = \frac{h}{45.3}

Solving for hh:

h=45.3×tan(60.2)h = 45.3 \times \tan(60.2^\circ)

Let's compute the height hh.The height of the building is approximately 79.1079.10 feet.

Would you like more details or have any further questions?

Here are 5 related questions for deeper understanding:

  1. How would the height change if the angle of elevation was 45° instead of 60° 12'?
  2. How can we use similar triangles to verify this calculation?
  3. How would the length of the shadow change if the building was taller?
  4. Can this method be applied to calculate the height of mountains using trigonometry?
  5. What is the relationship between the angle of elevation and the length of the shadow?

Tip: Always ensure angles are in the correct units (degrees or radians) when using trigonometric functions in calculations.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Angles of Elevation
Tangent Function

Formulas

tan(θ) = h / L
θ = 60° + 12' = 60.2°
h = L * tan(θ)

Theorems

Tangent Function in Right Triangles

Suitable Grade Level

Grades 9-11