There are many ropes keeping a hot air balloon from floating away before a balloon race. One of these ropes is tied to the ground at a [tex]$45^{\circ}$[/tex] angle. Another is tied to the ground at a [tex]$30^{\circ}$[/tex] angle.

If the hot air balloon is 21 feet off the ground, what is the distance between the ground directly underneath the balloon and the second rope, rounded to the nearest hundredth of a foot?

A. 12.12
B. 14.85
C. 29.70
D. 36.37



Answer :

Certainly! Let's solve this problem step-by-step.

1. Understanding the Problem:
- We have a hot air balloon that is 21 feet off the ground.
- There is a rope tied to the ground at a [tex]$30^\circ$[/tex] angle with the ground.
- We need to calculate the horizontal distance from the point directly underneath the balloon to the point where the second rope (tied at the [tex]$30^\circ$[/tex] angle) meets the ground.

2. Trigonometric Relationship:
- Given the height and the angle, we can use trigonometry to find the horizontal distance.
- We will use the tangent function, which relates the opposite side (height) to the adjacent side (horizontal distance) in a right triangle:
[tex]\[ \tan(\theta) = \frac{\text{opposite}}{\text{adjacent}} \][/tex]
- Here, the opposite side is the height of the balloon (21 feet), and the adjacent side is the distance we want to find.

3. Setting Up the Equation:
- Let [tex]\( \theta \)[/tex] be the angle of the rope with the ground, which is [tex]$30^\circ$[/tex].
- Let [tex]\( h \)[/tex] be the height of the balloon, which is 21 feet.
- Let [tex]\( d \)[/tex] be the horizontal distance we are solving for.
- Using the tangent function:
[tex]\[ \tan(30^\circ) = \frac{21}{d} \][/tex]

4. Solving for the Distance:
- Rearrange the equation to solve for [tex]\( d \)[/tex]:
[tex]\[ d = \frac{21}{\tan(30^\circ)} \][/tex]
- The value of [tex]\( \tan(30^\circ) \)[/tex] in degrees is approximately 0.5774.
- Plugging this value in, we get:
[tex]\[ d = \frac{21}{0.5774} \approx 36.3731 \][/tex]

5. Rounding to the Nearest Hundredth:
- The calculated distance is approximately 36.3731 feet.
- Rounding this to the nearest hundredth, we get 36.37 feet.

6. Conclusion:
- The horizontal distance between the point directly underneath the balloon and the point where the second rope meets the ground, rounded to the nearest hundredth of a foot, is [tex]\( \boxed{36.37} \)[/tex] feet.