Math Problem Statement
Solution
Let's solve the given problem step-by-step.
Problem Analysis:
- A lighthouse (A) has a lookout at the top. The angle of depression from A to a boat at point C is 30°.
- After 1 minute, the boat travels 50 m towards the lighthouse and is now at point B.
- The angle of elevation from point B to the lighthouse lookout is 60°.
Given Data:
- Distance m.
- Angle of depression from A to C: .
- Angle of elevation from B to A: .
Questions:
(a) Write down the value of in the diagram.
(b) Find the height of the lighthouse.
(c) Find the speed of the boat, in meters per second, from C to B.
Solution:
(a) Value of :
The value of is the angle at C, which is 60°. This is because and the angle of elevation at B to A is 60°.
Answer (a): .
(b) Height of the lighthouse:
Let the height of the lighthouse be . From the right triangle :
Using the tangent of the angle at B: Since :
Now, using the right triangle :
and since :
Given that :
Multiplying the entire equation by :
Simplify:
Answer (b): The height of the lighthouse is approximately 43.3 m.
(c) Speed of the boat:
The boat travels from C to B, a distance of 50 m, in 1 minute (60 seconds).
Speed:
Answer (c): The speed of the boat is approximately 0.833 m/s.
Would you like further details or explanations on any part? Here are some related questions:
- How would the height of the lighthouse change if the angles were different?
- Can you find the time taken if the boat was moving at a different speed?
- What other trigonometric ratios could be used to solve similar problems?
- How would you find the horizontal distance covered by the boat if it traveled in a different direction?
- How do changes in elevation angles affect distance measurements in trigonometry?
Tip: Always check the units of measurement when calculating speeds, distances, or heights to ensure consistency and accuracy.
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Math Problem Analysis
Mathematical Concepts
Trigonometry
Angle of Depression
Angle of Elevation
Tangent Function
Formulas
tan(θ) = opposite / adjacent
Speed = Distance / Time
Theorems
Trigonometric Ratios in Right-Angled Triangles
Suitable Grade Level
Grade 9-10
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