What is a bearing?
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What is a bearing?
A bearing is a way of describing and using a direction as an angle.
From which compass direction should a bearing always be measured?
A bearing should always be measured from North.
True or False?
Bearings are measured in an anti-clockwise direction.
False.
Bearings are measured in a clockwise direction.
How many figures must a bearing be written with?
A bearing must be written with 3 figures.
For angles under 100°, zero(es) should be used to fill in the missing figures, e.g. 059º, 008º.
True or False?
SOHCAHTOA and Pythagoras' theorem are frequently used in bearings questions.
True.
Pythagoras' theorem and SOHCAHTOA are frequently used in bearings questions.
This is because situations often include finding missing lengths or angles in right-angled triangles.
If a bearing of A from B is known, how do you find the bearing of B from A?
If a bearing of A from B is less than 180o, then add 180o to find the bearing of B from A.
E.g. if the bearing of A from B is 030o, then the bearing of B from A is 210o.
If a bearing of A from B is greater than 180o, then subtract 180o to find the bearing of B from A.
E.g. if the bearing of A from B is 270o, the bearing of B from A is 090o.
Which compass direction is indicated by a bearing of 090°?
When a bearing is 090°, it means due east.
True or False?
North should always be indicated on a diagram.
True.
North should always be indicated on a diagram as a point of reference.
What does it mean when a scale for a diagram is given as a ratio?
E.g. a scale of 1 : 10,000.
When the scale is given as a ratio (e.g., 1:10,000), it means that 1 unit on the diagram represents 10,000 of the same type of units in real life.
E.g. 1 cm on map = 10, 000 cm (or 100 m) in real life
How is a scale length on a map converted to a real-life length?
E.g. a length of 3 cm on a map with scale 1 : 20, 000.
To convert from a scale length to a real length, multiply by the scale factor.
E.g. 3 × 20 000 = 60 000 cm (600 m).
How is a real-life length converted to a scale length on a map?
E.g. a real-length of 15 km using a map with scale 1 : 50, 000.
To convert from a real length to a scale length, divide by the scale factor.
E.g. 15 ÷ 50, 000 = 0.000 3 km (30 cm).
True or False?
It may be helpful to convert the scale to more suitable units when dealing with very small or large scales.
True.
It may be helpful to convert the scale to more suitable units when dealing with very small or large scales.
For example, if 1 cm on a map represents 25,000 cm in real life, it may be easier to convert the units and use 1 cm represents 250 m or 0.25 km.
True or False?
Map scales are always given with units.
False.
Map scales are usually given in the form 1 : n with no reference to units.
What is an SSS triangle?
An SSS triangle is a triangle where you are given the lengths of all three sides.
What equipment do you need to accurately construct an SSS triangle?
Drawing an accurate SSS triangle requires the following equipment:
a sharp pencil,
a ruler
and a pair of compasses.
True or False?
Once you have constructed a given triangle you must erase the construction lines.
False.
To get full marks, you must leave your construction lines on your drawing as evidence of your working.