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for example: 2 = 4 then 2 , 3 , 4 , 6 are proportion
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And
2 is called the first proportion 3 is called the second proportion
4 is called the third proportion 6 is called the fourth proportion
also 2 and 6 is called the extremes
3 and 4 is called the means
the product of extremes = the product of means
2 X 6 = 3 X 4 = 12
Remark(2):
? If ( ?? = ?? ) , then (a x d = b x c). (Cross multiplication)
?? ??
? If a x d = b x c , then a, b, c and d are proportional
Which of the following ratios represent the proportion:
1) 12 , 4 2) 10 , 6
21 7 25 10
4 × 21 = 84 10 × 10 = 100
12 × 7 = 84 25 × 6 = 150
So, 12 = 4 (proportion) So, 10 = 6 (not proportion)
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21 25 10
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