PROPORTIONS 6-2. VOCABULARY Proportion – equality of two ratios Cross Products – the results...
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Transcript of PROPORTIONS 6-2. VOCABULARY Proportion – equality of two ratios Cross Products – the results...
PROPORTIONS
6-2
VOCABULARY
Proportion – equality of two ratiosCross Products – the results when you cross multiply
KEY CONCEPTS
In a proportion, the ratios and the cross products are equal to each other.Example:
6 = 8 `
9 12 72 = 72
Examples…
Tell whether the two ratios form a proportion.
1. 6 = 4 2. 15 = 5 9 6 20 7
36 = 36
yes
105 = 100
no
To solve a proportion that contains a variable, cross multiply.
Example: x = 4 `
9 66x = 36
Now you must get the x by itself, so reverse the operation.6x = 36
6 6
x = 6
REAL WORLD PROBLEM100 nautical miles equals about 115 standard miles. To the nearest mile, how far in standard miles is 156 nautical miles?
Nautical milesStandard miles
100 = 156 115 m100m = 17,940
100m = 17,940 100 100
m = 179.4 156 nautical miles is about 179 standard miles