Two airplanes leave an airport at the same time. An hour later, the planes are 300 km apart. If one plane has traveled 282 km and the other has traveled 150 km, what is the angle between their paths?

Carry your intermediate computations to at least four decimal places.
Round your answer to the nearest tenth of a degree.



Answer :

To solve the problem of finding the distance traveled by the second plane and the angle between their paths, we can follow these steps:

### Step 1: Identify Given Information
- Distance traveled by the first plane: [tex]\(282\)[/tex] km.
- Total distance apart after an hour: [tex]\(300\)[/tex] km.

### Step 2: Use the Pythagorean Theorem

The problem can be visualized as a triangle where:
- One side ([tex]\(a\)[/tex]) is the distance traveled by the first plane ([tex]\(282\)[/tex] km).
- The hypotenuse ([tex]\(c\)[/tex]) is the distance between the planes after an hour ([tex]\(300\)[/tex] km).

We want to find the distance traveled by the second plane ([tex]\(b\)[/tex]).

Using the Pythagorean Theorem:

[tex]\[ a^2 + b^2 = c^2 \][/tex]

Substitute the known values:

[tex]\[ 282^2 + b^2 = 300^2 \][/tex]

[tex]\[ 79524 + b^2 = 90000 \][/tex]

Solve for [tex]\(b^2\)[/tex]:

[tex]\[ b^2 = 90000 - 79524 \][/tex]

[tex]\[ b^2 = 10476 \][/tex]

Taking the square root of both sides to find [tex]\(b\)[/tex]:

[tex]\[ b = \sqrt{10476} \][/tex]

[tex]\[ b \approx 102.3523 \][/tex]

So, the distance traveled by the second plane is approximately [tex]\(102.3523\)[/tex] km.

### Step 3: Use the Law of Cosines to Find the Angle

To find the angle ([tex]\(\theta\)[/tex]) between the paths of the planes, we use the Law of Cosines:

[tex]\[ \cos(\theta) = \frac{a^2 + b^2 - c^2}{2ab} \][/tex]

Substitute the known values:

[tex]\[ \cos(\theta) = \frac{282^2 + 102.3523^2 - 300^2}{2 \cdot 282 \cdot 102.3523} \][/tex]

Calculate the numerator and denominator separately:

[tex]\[ \cos(\theta) = \frac{79524 + 10476 - 90000}{2 \cdot 282 \cdot 102.3523} \][/tex]
[tex]\[ \cos(\theta) = \frac{0}{2 \cdot 282 \cdot 102.3523} \][/tex]
[tex]\[ \cos(\theta) = 0 \][/tex]

### Step 4: Determine the Angle

Since [tex]\(\cos(\theta) = 0\)[/tex], we know that:

[tex]\[ \theta = \cos^{-1}(0) \][/tex]

The corresponding angle is:

[tex]\[ \theta = 90^\circ \][/tex]

### Final Answer

The second plane has traveled approximately [tex]\(102.4\)[/tex] km, and the angle between their paths is [tex]\(90.0^\circ\)[/tex] rounded to the nearest tenth of a degree.