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# Proportion

Math Performance Task on Proportion Subtopics: Direct Proportion, Indirect Porportion, Maps and Scales
by

## Angie QuanHui Vanessa Isabelle Math

on 2 March 2011

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#### Transcript of Proportion

Proportion DIRECT PROPORTION INVERSE PROPORTION MAPS AND SCALES when 2 quantities change
by the same factor eg. a = b Directly Proportional Don't get it? (: 1 pencil cost \$1. So 3
pencils costs \$3. 5 pencils
cost \$5. The total cost is
Directly Proportional to the number of pencils for the linguists for the visual people :D table Any graph that has a straight line is a linear graph of direct proportion Example of a linearliy increasing graph of direct proportion The cost of 1 apple is twice
the cost of an eraser. These
two items are in direct
proportion. What is your 1st impression of 'Inverse proportion'?
Sounds 'chim'? NO... You are smarter than you think. You learnt it in primary school Think of it: The more chips I eat, I become unhealthier. So technically, I know when 2 subjects are inversely proportional if:
x decreases when y increases or vice- versa So, how to apply inverse proportion in real life?
Simple. Just take for example, John takes 1 hour to do 2
Math Worksheets. So if there is only 1 Worksheet, and assuming
that he does the worksheet at a uniform rate, the time taken for
him to finish would be reduced. The time therefore is inversely proportional to the number of Worksheets John has. It takes them 2.8 days 18 men build a house in 6
days. I the number of men
become 30, and assuming they
work at the same rate, how long
will they take to build the house? Map Scale: The relationship between distances on a map and the corresponding distances on the earth's surface expressed as a fraction or a ratio Many different units
of measurement eg. 1cm
100cm on actual ground for Map scale and
1cm to 10 000cm on actual ground Reason for Map and Area Scale: A map cannot be of the same size as the length and area it represents, therefore, it is scaled down in proportion so that it can fit in a small area Large scale maps are 1:24,000 and larger.
Intermediate scale maps occur in the 1:50,000
to 1:100,000 scale range. Small scale maps are
1:250,000 and smaller. Map Scale= Map distance: Actual Distance
Area Scale= Area on Map: Actual Area A particular map shows a scale of 1 : 5000.
What is the actual distance if the map distance is 8 cm?

Map distance: Actual distance= 1: 5000
Actual distance if map distance is 8 cm= 8x 5000 cm
= 40 000 cm
= 400 m The End Thank You graph Any Questions? x y Area Scale: The relationshipbetween the area
on a map and the corresponding area on earth's
surface expressed as a fraction or ratio 2 2 Representative Fraction(RF) is the
indication of the scale eg. 1unit rep.100cm
etc. Expressed as fraction or ration and the numerator for fraction is always 1
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