# geometry and measures

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?- Created by: bio1423
- Created on: 16-06-13 12:18

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- Geometry and measures
- metric and imperial units
- metric
- length; 10mm=1cm 100cm=1m 1000m=1km
- weight; 1000mg=1g 1000g=1kg 1000kg=1tonne
- capacity; 1000ml=1litre 100cl=1litre 1000cm3=1litre

- Imperial
- length; 1foot=12inches 1yard=3feet
- weight; 1stone=14pounds 1pound=16ounces
- capacity; 20fluid oz=1pint 8pints =1gallon

- Comparisons between metric and imperial
- length; 2.5cm=1inch 30cm=1foot 1m=39inches 8km=5miles
- weight; 25g=1oz 1kg=2.2lb
- Capacity; 1litre=1.75pints 4.5litres=1gallon

- metric
- compound measures
- Average speed=total distance/total time taken
- combination of 2 or more measures
- Time = distance/speed
- Density = mass/volume
- mass=density x volume
- Volume = mass/ density

- Accuracy of measurement
- Discrete measures can be counted
- Continuous measures need a measuring instrument
- are not exact, eg. to nearest kg

- Transformations 1
- changes the position or size of a shape
- Translations
- moves a figure from one place to another
- Vectors used to describe distance & direction
- Vector written as a b
- a = horizontal movement
- b = vertical movement

- Reflections
- creates an image of an object in other side of mirror line
- mirror line known as axis of reflection
- size and shape not changed
- when describing, write equation of mirror line

- Rotations
- turns a figure through an angle about a fixed point
- fixed point called centre of rotation
- wen describing give centre of rotation, direction, angle of turn

- Transformations 2
- Enlargements
- change size but not shape
- centre of enlargement is point from which enlargement takes place
- scale factor; how many times original lengths increased
- sf>1, shape gets bigger
- Untitled

- Enlargements

- metric and imperial units

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