NTA Abhyas JEE Main2020MathematicsHeights and DistancesPractice
A tower subtends an angle of 6 0 o at a point on the same level as the foot of the tower and at a second point just 10 meters above the first point the angle of depression of the foot of the tower is 1 5 o . The height of the tower is (in meters)
Options
- A10 3 2 - 3
- B10 3 2 - 3
- C10 3 2 + 3
- D10 3 2 + 3
Correct answer
D. 10 3 2 + 3
Step-by-step solution
In the figure A B is the vertical tower and C , D are the two points Now, in right angled Δ A B D A B B D = tan ⁡ 60 o ∴ h x = tan ⁡ 60 o ⇒ h = 3 x … 1 In right angled Δ B C E ,   B E E C = tan ⁡ 15 o ∴ 10 x = tan ⁡ 15 o   ⇒ x = 10 tan ⁡ 15 o … 2 From 1 and 2 , we get   h = 10 tan ⁡ 15 o × 3 = 10 3 2 + 3 meters