A boat is heading towards a lighthouse, where Madeline is watching from a vertical distance of 140 feet above the water. Madeline measures an angle of depression to the boat at point \( A \) to be \( 5^{\circ} \). At some later time, Madeline takes another measurement and finds the angle of depression to the boat (now at point \( B \) ) to be \( 50^{\circ} \). Find the distance from point \( A \) to point \( B \). Round your answer to the nearest tenth of a foot if necessary.
Solución de tutoría real
Responder
Solución
Revisado y aprobado por el equipo de tutoría de UpStudy
Mind Expander
To solve the problem, we will begin by using the given angles and the height of Madeline's observation point to find the horizontal distances from the boat to the lighthouse at points A and B. 1. **Calculate the horizontal distance at point A:** Madeline's height is \( h = 140 \) feet and the angle of depression to the boat at point A is \( 5^\circ \). Using the tangent function: \[ \tan(5^\circ) = \frac{h}{d_A} \] Rearranging gives: \[ d_A = \frac{h}{\tan(5^\circ)} = \frac{140}{\tan(5^\circ)} \approx \frac{140}{0.0875} \approx 1600 \text{ feet} \] 2. **Calculate the horizontal distance at point B:** For point B, the angle of depression is \( 50^\circ \): \[ \tan(50^\circ) = \frac{h}{d_B} \] Rearranging gives: \[ d_B = \frac{h}{\tan(50^\circ)} = \frac{140}{\tan(50^\circ)} \approx \frac{140}{1.1918} \approx 117.5 \text{ feet} \] 3. **Find the distance from A to B:** The distance from point A to point B is simply the difference in horizontal distances: \[ \text{Distance from A to B} = d_A - d_B \approx 1600 - 117.5 \approx 1482.5 \text{ feet} \] Now, rounding this to the nearest tenth of a foot gives us the final answer: \[ \text{Distance from A to B} \approx 1482.5 \text{ feet} \]