8.1 Geo Bauer.notebook
A ratio is a quotient of two
numbers... typically in lowest
terms.
December 17, 2014
(8.1) Ratio & Proportion
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The slope of a line is a common
example of a ratio.
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On the bottom of model cars it usually shows the ratio of the model size to the actual size.
(0, 0)
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Means and Extremes
A proportion is an equation stating that ratios are equal.
Extreme
1st term
3rd term
2nd term
4th term
Mean
Mean
Extreme
Extreme
Extreme
4th term
1st term
Mean
2nd term
Mean
3rd term
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8.1 Geo Bauer.notebook
Means­Extremes Products
If , then December 17, 2014
Means­Extremes Ratio Theorem
If
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, ⇒
and
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The Geometric Mean
In a mean proportion, the means are the same.
Examples:
Find the geometric mean between 2 and 32.
Definition: If the means of a proportion are =, ⇒ either mean is called the geometric mean between the extremes.
Find the arithmetic mean between 2 and 32.
also called the mean proportional
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8.1 Geo Bauer.notebook
December 17, 2014
If 12x = 20y, find the ratio of x to y.
Examples:
Find the mean proportional between 5 and 45.
Find the arithmetic mean between 5 and 45.
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Are these two proportions equivalent? Show your reasoning.
Another Method to Show Equivalency of Proportions
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8.1 Geo Bauer.notebook
December 17, 2014
(8.1) Pg. 329: 2, 3, 11, 15, 18, 21, 24
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