Math Problem Statement

The bearing from A to C is S 57​° E. The bearing from A to B is N 88​° E. The bearing from B to C is S 33​° W. A plane flying at 250 mph takes 2.8 hr to go from A to B. Find the distance from A to C.

The distance from A to C is

enter your response here mi.

Solution

To solve this problem, we will use trigonometry, specifically the law of sines, since we are dealing with a triangle and we have bearings that will allow us to find the angles of this triangle.

Step 1: Determine the angles of the triangle.

  • The bearing from A to C is 57 E\text{S } 57^\circ \text{ E}. This means the angle between the south direction and the line AC is 5757^\circ.
  • The bearing from A to B is 88 E\text{N } 88^\circ \text{ E}. This means the angle between the north direction and the line AB is 8888^\circ.
  • The bearing from B to C is 33 W\text{S } 33^\circ \text{ W}. This means the angle between the south direction and the line BC is 3333^\circ.

Step 2: Calculate the angle at A.

  • The angle BAC\angle BAC can be found by subtracting the bearing from A to B from the bearing from A to C.

    BAC=8857=31\angle BAC = 88^\circ - 57^\circ = 31^\circ

Step 3: Calculate the angle at B.

  • The angle ABC\angle ABC is calculated by subtracting the bearing from B to C from the bearing from A to B.

    ABC=88+33=121\angle ABC = 88^\circ + 33^\circ = 121^\circ

Step 4: Calculate the angle at C.

  • The angle ACB\angle ACB in the triangle can be calculated as:

    ACB=180BACABC\angle ACB = 180^\circ - \angle BAC - \angle ABC ACB=18031121=28\angle ACB = 180^\circ - 31^\circ - 121^\circ = 28^\circ

Step 5: Calculate the distance from A to B.

  • The distance from A to B can be calculated using the speed and time:

    Distance from A to B=Speed×Time=250 mph×2.8 hr=700 miles\text{Distance from A to B} = \text{Speed} \times \text{Time} = 250 \text{ mph} \times 2.8 \text{ hr} = 700 \text{ miles}

Step 6: Apply the law of sines to find the distance from A to C.

  • The law of sines states:

    ABsin(ACB)=ACsin(ABC)\frac{\text{AB}}{\sin(\angle ACB)} = \frac{\text{AC}}{\sin(\angle ABC)}

    Solving for AC\text{AC}: AC=AB×sin(ABC)sin(ACB)\text{AC} = \text{AB} \times \frac{\sin(\angle ABC)}{\sin(\angle ACB)}

    Substituting the values: AC=700×sin(121)sin(28)\text{AC} = 700 \times \frac{\sin(121^\circ)}{\sin(28^\circ)}

Step 7: Calculate the distance using a calculator.

Let's compute this.

sin(121)0.8572\sin(121^\circ) \approx 0.8572 sin(28)0.4695\sin(28^\circ) \approx 0.4695 AC=700×0.85720.4695700×1.8261278.2 miles\text{AC} = 700 \times \frac{0.8572}{0.4695} \approx 700 \times 1.826 \approx 1278.2 \text{ miles}

So, the distance from A to C is approximately 1278.2 miles.

Would you like more details or have any questions?

Related Questions

  1. How would the distance change if the speed of the plane was different?
  2. What would be the bearing from C to A?
  3. How can the Law of Cosines be used in this situation?
  4. If the plane had taken a different route, what other factors would need consideration?
  5. What is the significance of knowing the bearings in navigation?

Tip

Always double-check your angle calculations when working with bearings, as small errors can lead to significant discrepancies in the final results.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Law of Sines
Bearings

Formulas

Law of Sines: AB/sin(∠ACB) = AC/sin(∠ABC)

Theorems

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Suitable Grade Level

High School