A TV tower stands vertically on a bank of canal . from a point on the ...
Given information:
- The angle of elevation of the top of the tower from a point directly opposite the tower is 60 degrees.
- From another point 20m away from the first point, on the line joining this point to the foot of the tower, the angle of elevation of the top of the tower is 30 degrees.
Let's solve this problem step by step:
Step 1: Drawing a diagram
First, let's draw a diagram to visualize the given information.
```
T
/|
/ |
/ | h
/ |
/ |
D / |
| / |
| / |
| / |
| / |
|/ |
P-----------O
20m
```
- T: Top of the tower
- D: Foot of the tower
- P: First point on the other bank directly opposite the tower
- O: Second point, 20m away from point P on the line joining P to D
Step 2: Identifying the right-angled triangles
From the diagram, we can identify two right-angled triangles:
- Triangle TOP: This triangle has the top of the tower as the top vertex, the foot of the tower as the bottom vertex, and the line joining P to D as the hypotenuse.
- Triangle POD: This triangle has point P as the top vertex, the foot of the tower as the bottom vertex, and point O as the right-angle vertex.
Step 3: Solving for the height of the tower
In triangle TOP, we can use trigonometry to find the height of the tower (h).
- In triangle TOP, the angle of elevation of the top of the tower from point P is 60 degrees. Therefore, the angle between the hypotenuse and the base is 90 - 60 = 30 degrees.
- We can use the tangent function to find h. tan(30) = h / 20m.
- Rearranging the equation, h = 20m * tan(30).
Step 4: Solving for the width of the canal
In triangle POD, we can use trigonometry to find the width of the canal (x).
- In triangle POD, the angle of elevation of the top of the tower from point P is 30 degrees. Therefore, the angle between the base and the hypotenuse is 90 - 30 = 60 degrees.
- We can use the cosine function to find x. cos(60) = x / 20m.
- Rearranging the equation, x = 20m * cos(60).
Step 5: Calculating the values
Using a scientific calculator, we can calculate the values of h and x:
- h = 20m * tan(30) ≈ 20m * 0.577 ≈ 11.54m
- x = 20m * cos(60) ≈ 20m * 0.5 ≈ 10m
Step 6: Final answer
The height of the tower is approximately 11.54m and the width of the canal is approximately 10m.
A TV tower stands vertically on a bank of canal . from a point on the ...
Is this from rd sharma
To make sure you are not studying endlessly, EduRev has designed Class 10 study material, with Structured Courses, Videos, & Test Series. Plus get personalized analysis, doubt solving and improvement plans to achieve a great score in Class 10.