Home
Class 12
MATHS
A stationary balloon is observed from th...

A stationary balloon is observed from three points A, B and C on the plane ground and is found point is `60^(@)`. If `angleABC=30^(@)` and AC = 5 meters, then the height of the balloon from the ground is

A

`5sqrt2` meters

B

`(5)/(4)sqrt3` meters

C

`(5)/(sqrt3)` meters

D

`(5)/(4sqrt3)` meters

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to find the height of the balloon (denoted as \( h \)) from the ground, given the angles and distances involved. ### Step-by-Step Solution: 1. **Understanding the Geometry**: - We have three points \( A \), \( B \), and \( C \) on the ground. - The angle of elevation from each point to the balloon is \( 60^\circ \). - The angle \( \angle ABC = 30^\circ \). - The distance \( AC = 5 \) meters. 2. **Identify the Right Triangle**: - The height of the balloon can be represented as the perpendicular from point \( P \) (the balloon) to the line \( AC \). - Let \( PQ \) be the height of the balloon, which is \( h \). 3. **Using Trigonometric Ratios**: - In triangle \( PAQ \) (where \( Q \) is the foot of the perpendicular from \( P \) to line \( AC \)), we can use the cotangent function: \[ \cot(60^\circ) = \frac{h}{PA} \] - We know that \( \cot(60^\circ) = \frac{1}{\sqrt{3}} \), thus: \[ h = PA \cdot \cot(60^\circ) = PA \cdot \frac{1}{\sqrt{3}} \] 4. **Finding \( PA \)**: - Since \( P \) is the circumcenter of triangle \( ABC \), the distances \( PA \), \( PB \), and \( PC \) are equal. Let this common distance be \( R \). - Therefore, we have: \[ PA = R = \frac{h}{\sqrt{3}} \] 5. **Using the Sine Rule in Triangle \( ABC \)**: - In triangle \( ABC \): \[ \sin(30^\circ) = \frac{AC}{BC} \] - Given \( AC = 5 \): \[ \sin(30^\circ) = \frac{1}{2} \Rightarrow BC = \frac{AC}{\sin(30^\circ)} = \frac{5}{\frac{1}{2}} = 10 \] 6. **Relating \( BC \) to the Circumradius**: - The circumradius \( R \) is half of \( BC \) since \( P \) is the circumcenter: \[ R = \frac{BC}{2} = \frac{10}{2} = 5 \] 7. **Substituting Back to Find \( h \)**: - Now substituting \( R = 5 \) into the equation \( R = \frac{h}{\sqrt{3}} \): \[ 5 = \frac{h}{\sqrt{3}} \Rightarrow h = 5\sqrt{3} \] ### Final Answer: The height of the balloon from the ground is \( h = 5\sqrt{3} \) meters.
Promotional Banner

Topper's Solved these Questions

  • NTA JEE MOCK TEST 54

    NTA MOCK TESTS|Exercise MATHEMATICS|25 Videos
  • NTA JEE MOCK TEST 56

    NTA MOCK TESTS|Exercise MATHEMATICS|25 Videos

Similar Questions

Explore conceptually related problems

A spherical balloon of radius 10 feet is in the open air. If angle of elevation of centre of the balloon from a point on the ground is 45^(@) and spherical balloon subtens on angle of 45^(@) on that point then how high is the centre of the balloon from the ground ?

If the angle of elevation of a baloon from two consecutive kilometre -stones along a road are 30^(@)and60^(@) respectively , then the height of the balloon above the ground will be

If the angles of elevation of a ballon from the two consecultive kilometre stones along a road are 30^@ and 60^@ respectively, then the height of the balloon above the ground will be

A balloon is observed simultaneously from three points A,B and C on a straight road directly under it.The angular elevation at B is twice and at C is thrice that at A .If the distance between A and B is 200metres and the distance between B and C is 100metres, then find the height of balloon above the road.

An aeroplane flying at a height 300 metre above the ground passes vertically above another plane at an instant when the angles of elevation of the two planes from the same point on the ground are 60^(@) and 45^(@) respectively.Then the height of the lower plane from the ground in metres is

A stone is dropped from a stationary hot air balloon in the air travels 14.7m in the last second before it hits the ground. Find the height of the balloon from the ground.

NTA MOCK TESTS-NTA JEE MOCK TEST 55-MATHEMATICS
  1. Let alpha and beta are two positive roots of x^(2)-2ax+ab=0 where 0ltb...

    Text Solution

    |

  2. If (x^(4)+2x i)-(3x^(2)+yi)=(3-5i)+(1+2yi) then the number of ordere...

    Text Solution

    |

  3. A stationary balloon is observed from three points A, B and C on the p...

    Text Solution

    |

  4. The number of solutions of the equation sin^(-1)x=(sinx)^(-1) is/are

    Text Solution

    |

  5. The mean of n observation is barX. If the first observation is increas...

    Text Solution

    |

  6. If the normal at P(18, 12) to the parabola y^(2)=8x cuts it again at Q...

    Text Solution

    |

  7. If f:R rarrR is a function, then f is

    Text Solution

    |

  8. The possible value of the ordered triplet (a, b, c) such that the func...

    Text Solution

    |

  9. If the line y=x+c touches the hyperbola (x^(2))/(9)-(y^(2))/(5)=1 at t...

    Text Solution

    |

  10. The solution of the differential equation (dy)/(dx)=(y^(2)+xlnx)/(2xy)...

    Text Solution

    |

  11. The value of intsin^(3)x sqrt(cosx)dx is equal to (where, c is the con...

    Text Solution

    |

  12. A random variable X follows binomial probability distribution with pro...

    Text Solution

    |

  13. Equation of the plane passing through the point (1, -1, 3), parallel t...

    Text Solution

    |

  14. If the system of equations x+y+z=6, x+2y+lambdaz=10 and x+2y+3z=mu has...

    Text Solution

    |

  15. The number of five digit numbers that contains 7 exactly once is equal...

    Text Solution

    |

  16. The points (-2, -1), (1, 0), (4, 3) and (1, 2) are

    Text Solution

    |

  17. The value of a such that the area bounded by the curve y=x^(2)+2ax+3a^...

    Text Solution

    |

  18. Number of common points to the curves C(1){(-1+2cos alpha, 2 sin alpha...

    Text Solution

    |

  19. If the magnitude of the projection of the vector hati-hatj+2hatk on th...

    Text Solution

    |

  20. The value of int(0)^(2)((x^(2)-2x+4)sin(x-1))/(2x^(2)-4x+5)dx is equal...

    Text Solution

    |