E q u i v a l e n t r a t i o s :
A ratio consists of two or more numbers that compare the parts or shares of things of the same type,
in the same units
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Ex. 1:2 (for every 1 part x, you need 2 parts y)
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Equivalent ratios are equal ratios- similar to equivalent fractions in many ways
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To find an equivalent ratio, multiply or divide each term by the same number, or enter the ratio as a
fraction in your calculator and simplify it there
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Ex.
S i m p l i f y i n g r a t i o s :
r a t i o p r o b l e m s :
Problems involving ratios can be solved using equivalent ratios or the unitary method
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With the unitary method we find the size of one part first
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Note: this is an example of the unitary method with
ratios -
S c a l e m a p s a n d p l a n s :
Scale maps and plans are a special application of ratios used to represent real locations and buildings.
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Lengths and distances on the scale diagrams are in the same ratio as the real lengths and distances.
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Ex. The scale 1:100 means that the real lengths are 100 times larger than the scaled length
Map scales are also used with the same ratios, except this time they use measuring units at the end
Eg. 1 cm on the map : 1 km in real life
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Eg.
Scale = 5 cm : 10 km
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5 cm : 10 *1000 *100 cm (convert km to cm)
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5 cm : 1 000 000 cm
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Scale is = 1:200 000 (simplify the ratio - divide)
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Chapter 11: Rates, Ratios & Time.
Tuesday, 12 October 2021
5:38 PM
