Knowee
Questions
Features
Study Tools

Town B is on a bearing of 116° from town A. Town C is on a bearing 204° from town B. Town C isdue south and 23 km from town A. Find the distance of town B from town C. Give your answers to 3significant figures.[1]2. Sine and Cosine RulesName: Class: Date:Copyright Mathster.com 2014. Licensed by Your School with permission to redistribute

Question

Town B is on a bearing of 116° from town A. Town C is on a bearing 204° from town B. Town C isdue south and 23 km from town A. Find the distance of town B from town C. Give your answers to 3significant figures.[1]2. Sine and Cosine RulesName: Class: Date:Copyright Mathster.com 2014. Licensed by Your School with permission to redistribute

🧐 Not the exact question you are looking for?Go ask a question

Solution

To solve this problem, we need to use trigonometry and the sine and cosine rules. Let's break it down step by step.

  1. Understanding the Bearings and Positions:

    • Town B is on a bearing of 116° from town A.
    • Town C is on a bearing of 204° from town B.
    • Town C is due south and 23 km from town A.
  2. Visualizing the Problem:

    • Draw a diagram with town A at the origin.
    • Draw a line from A to B at an angle of 116° from the north.
    • Draw a line from B to C at an angle of 204° from the north.
    • Draw a vertical line from A to C, which is 23 km.
  3. Finding the Angles:

    • The bearing of 116° from A to B means the angle between the north direction and line AB is 116°.
    • The bearing of 204° from B to C means the angle between the north direction and line BC is 204°.
    • Since town C is due south of town A, the angle between the north direction and line AC is 180°.
  4. Calculating the Angle at Town B:

    • The angle between line AB and line AC is 116° - 180° = -64° (which is equivalent to 296° in a positive direction).
    • The angle between line BC and line AC is 204° - 180° = 24°.
    • Therefore, the angle at town B (angle ABC) is 180° - 24° = 156°.
  5. Using the Sine Rule:

    • We need to find the distance BC.

    • In triangle ABC, we know:

      • Angle BAC = 116°
      • Angle ABC = 156°
      • Side AC = 23 km
    • Using the sine rule: BCsin(116°)=23sin(156°) \frac{BC}{\sin(116°)} = \frac{23}{\sin(156°)}

  6. Solving for BC:

    • Calculate the sines: sin(116°)0.8829 \sin(116°) \approx 0.8829 sin(156°)0.4067 \sin(156°) \approx 0.4067

    • Substitute these values into the sine rule: BC0.8829=230.4067 \frac{BC}{0.8829} = \frac{23}{0.4067}

    • Solve for BC: BC=23×0.88290.406749.9 km BC = \frac{23 \times 0.8829}{0.4067} \approx 49.9 \text{ km}

Therefore, the distance of town B from town C is approximately 49.9 km to 3 significant figures.

This problem has been solved

Similar Questions

A , B and C are three shops such that B is 600 m due East of A. The bearing of C from A is 144∘ . The bearing of C from B is 240∘ . Find the distance AC, correct to 1 decimal place.Please give 1 answer.302.0 m301.6 m301.0 m301.7 m

The bearing of A from B is 225°Work out the bearing of B from A.[3 marks]Answer °Turn over for the next questionNot drawnaccurately225°NBAN6

find the bearing of A from B if the bearing of Bfrom A is 025°

Two ships, A and B, leave a port at 11:00.A travels on a bearing of 080° at a speed of 25km/h.B travels on a bearing of 152° at a speed of 20km/h.(a) Work out the distance between A and B at 14:00.(b) Work out the bearing of B from A at 14:00. (Give your answer to 2 decimal places)

John drives from town A to town B at speed of 60 mph. After two hours, Mark leaves town A for town B at a speed of 75 mph. How much time does Mark take to reach town B if both of them reach town B at the same time?

1/2

Upgrade your grade with Knowee

Get personalized homework help. Review tough concepts in more detail, or go deeper into your topic by exploring other relevant questions.