Scale drawings and bearings

We have looked at scale drawings and angles already in the course.

The drawing below is a scale drawing. The line in the bottom left represents 5km. The length of the line from Dover to Calais is 8.77 \times longer than the line in the bottom left.

What is the straight-line distance from Dover to Calais in kilometres to one decimal place?

It is 5 \times 8.77 = 43.9km

The bearing from Dover to Calais is shown on the picture to be 116^circ

What is the bearing from Calais to Dover?

We can calculate this by knowing that the angle of a straight line is 180^circ

The bearing back to Dover is 116 + 180 = 296^circ