Math Problem Statement

Isaiah is trying to find the height of a radio antenna on the roof of a local building. He stands at a horizontal distance of 20 meters from the building. The angle of elevation from his eyes to the roof left parenthesis(point AAright parenthesis) is 32degrees ∘, and the angle of elevation from his eyes to the top of the antenna left parenthesis(point BBright parenthesis) is 43degrees ∘ . If his eyes are 1.62 meters from the ground, find the height of the antenna left parenthesis(the distance from point AA to point BBright parenthesis). Round your answer to the nearest meter if necessary.

Solution

To find the height of the antenna, we need to determine the height of the building first and then the total height up to the top of the antenna. Finally, we subtract the building height from the total height to get the antenna height.

Step 1: Define Given Information

  • Distance from Isaiah to the base of the building: 20 meters
  • Angle of elevation to the roof of the building (Point A): 32°
  • Angle of elevation to the top of the antenna (Point B): 43°
  • Eye level height: 1.62 meters

Let:

  • hAh_A be the height of the building above Isaiah's eyes.
  • hBh_B be the height of the antenna above Isaiah's eyes.
  • HAH_A be the total height of the building (including the height from the ground).
  • HBH_B be the total height of the building and antenna.

Step 2: Use Trigonometry

Using the tangent function:

tan(θ)=oppositeadjacent\tan(\theta) = \frac{\text{opposite}}{\text{adjacent}}

Find hAh_A:

tan(32)=hA20\tan(32^\circ) = \frac{h_A}{20}

hA=20×tan(32)h_A = 20 \times \tan(32^\circ)

hA12.5 metersh_A \approx 12.5 \text{ meters}

Total building height:

HA=hA+1.62H_A = h_A + 1.62

HA=12.5+1.62=14.12 metersH_A = 12.5 + 1.62 = 14.12 \text{ meters}

Find hBh_B:

tan(43)=hB20\tan(43^\circ) = \frac{h_B}{20}

hB=20×tan(43)h_B = 20 \times \tan(43^\circ)

hB18.7 metersh_B \approx 18.7 \text{ meters}

Total height to the top of the antenna:

HB=hB+1.62H_B = h_B + 1.62

HB=18.7+1.62=20.32 metersH_B = 18.7 + 1.62 = 20.32 \text{ meters}

Step 3: Compute Antenna Height

Antenna height=HBHA\text{Antenna height} = H_B - H_A

=20.3214.12= 20.32 - 14.12

=6.2 meters= 6.2 \text{ meters}

Final Answer:

The antenna is 6 meters tall (rounded to the nearest meter).


Would you like a more detailed explanation or a diagram?

Related Questions:

  1. How would the answer change if the distance from Isaiah to the building was different?
  2. What if Isaiah's eye level was different?
  3. How can we verify the calculations using another trigonometric function?
  4. How would the problem change if the antenna was on a sloped roof?
  5. How do we solve a similar problem when given different angles?

Tip:

Always double-check your tangent values to ensure accuracy when solving height-related problems!

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Tangent Function
Angle of Elevation
Height Calculation

Formulas

tan(θ) = opposite / adjacent

Theorems

Tangent Function for Right Triangles

Suitable Grade Level

Grades 9-11