Bearings and Scale Drawings
Describe a direction as a three-figure bearing measured clockwise from north, and use a scale drawing to move between a plan and real distances.
What a learner can do afterwards
- Measure and write a bearing as three figures, including bearings past 180 degrees
- Find the back bearing of a stated direction and justify the calculation
- Construct a scale drawing from bearings and distances, then read a real distance off it
1 · Read
A bearing is a direction counted clockwise from north, always in three figures. Due east is 090 degrees, south is 180 degrees, and anything past 180 keeps its digits, like 200 degrees.
There-and-back legs differ by half a turn, which is 180 degrees. If the bearing is below 180, add 180 for the way back. If it is past 180, subtract 180 instead.
Draw a scale leg in three moves: rule a north line, turn clockwise to the bearing, then draw the scaled length. A 4 km leg due east at 1 cm to 1 km draws 4 cm. A 6 cm leg at 1 cm to 2 km stands for 12 km sailed.
Give every bearing three figures, even small ones. A bearing of 60 degrees is written 060 degrees. Missing that leading zero is the classic lost mark.
Count clockwise from north in three figures, reverse with half a turn, and let the scale turn centimetres into kilometres.
2 · Watch
Take it off screen
Where it sits
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.