We read your photo as:

A ship sails from Port A on a bearing 065° to Port B a distance 54 km. It then sails on the bearing of 155° from B to Port C a distance of 80 km. Find correct to one decimal place: (i) The distance be

Mathematics

ScanSolve AI Answer

Answer

b(ii)

96.5 km96.5 \text{ km}

121.0∘121.0^\circ

Step-by-step solution

3 steps

here's the solution for part (b):

Part b(i)

The distance between A and C

Navigation Problem

A ship sails from Port A on a bearing 065∘065^\circ to Port B a distance 54 km54 \text{ km}. It then sails on the bearing of 155∘155^\circ from B to Port C a distance of 80 km80 \text{ km}. Find correct to one decimal place:

Part b(ii)

96.5 km96.5 \text{ km}

The bearing of C from A.

  1. Determine the angle ∠ABC\angle ABC.

    Draw a North line at Port A and Port B. Since these North lines are parallel, we can use properties of parallel lines.
    The bearing of B from A is 065∘065^\circ. This means the angle between the North line at A and the line segment AB is 65∘65^\circ.
    The alternate interior angle between the line segment AB and the South line at B is also 65∘65^\circ.
    The bearing of C from B is 155∘155^\circ. This is the angle measured clockwise from the North line at B to the line segment BC.
    The angle between the North line at B and the South line at B is 180∘180^\circ.
    Therefore, the angle between the South line at B and the line segment BC is 180∘−155∘=25∘180^\circ - 155^\circ = 25^\circ.
    The angle ∠ABC\angle ABC is the sum of the angle between AB and the South line at B, and the angle between the South line at B and BC.

    ∠ABC=65∘+25∘=90∘\angle ABC = 65^\circ + 25^\circ = 90^\circ
  2. Calculate the distance AC using the Cosine Rule.

    In △ABC\triangle ABC, we have AB=54 kmAB = 54 \text{ km}, BC=80 kmBC = 80 \text{ km}, and ∠ABC=90∘\angle ABC = 90^\circ.
    Since ∠ABC=90∘\angle ABC = 90^\circ, we can use the Pythagorean theorem (a special case of the Cosine Rule).

    AC2=AB2+BC2AC^2 = AB^2 + BC^2 AC2=(54 km)2+(80 km)2AC^2 = (54 \text{ km})^2 + (80 \text{ km})^2 AC2=2916 km2+6400 km2AC^2 = 2916 \text{ km}^2 + 6400 \text{ km}^2 AC2=9316 km2AC^2 = 9316 \text{ km}^2 AC=9316 kmAC = \sqrt{9316} \text{ km} AC≈96.5194 kmAC \approx 96.5194 \text{ km}

    Rounding to one decimal place:

    AC≈96.5 kmAC \approx 96.5 \text{ km}

    The distance between A and C is 96.5 km\boxed{96.5 \text{ km}}.

  3. Calculate the bearing of C from A.

    First, find the angle ∠BAC\angle BAC in △ABC\triangle ABC. Since it's a right-angled triangle:

    tan⁡(∠BAC)=OppositeAdjacent=BCAB\tan(\angle BAC) = \frac{\text{Opposite}}{\text{Adjacent}} = \frac{BC}{AB} tan⁡(∠BAC)=8054\tan(\angle BAC) = \frac{80}{54} ∠BAC=arctan⁡(8054)\angle BAC = \arctan\left(\frac{80}{54}\right) ∠BAC≈55.99∘\angle BAC \approx 55.99^\circ

    The bearing of C from A is the sum of the bearing of B from A and the angle ∠BAC\angle BAC.
    Bearing of C from A = 065∘+∠BAC065^\circ + \angle BAC
    Bearing of C from A = 065∘+55.99∘065^\circ + 55.99^\circ
    Bearing of C from A = 120.99∘120.99^\circ
    Rounding to one decimal place:
    Bearing of C from A ≈121.0∘\approx 121.0^\circ
    The bearing of C from A is 121.0∘\boxed{121.0^\circ}.

Was this helpful?

Try one yourself

A new problem that tests the same skill.

Still stuck on this one?

Ask a follow-up, and the answer starts from this question.

Got a different question?Ask your own question
Handwritten step-by-step solution preview

Handwritten Step-by-Step Solution

Get this as a handwritten image on WhatsApp — like a tutor wrote it for you.

Try on WhatsApp