Scale Factor of 21 and 18

What is the Scale Factor of 21 and 18? What is the Scale Factor between 21 and 18? More specifically, what is the Scale Factor from a length of 21 to a length of 18? In other words, what (Scale Factor) can you multiply by 21 to get 18 as illustrated below?:

21 × Scale Factor = 18

To solve the equation above, you simply divide both sides by 21 to get the Scale Factor alone on the left side:

(21 × Scale Factor)/21 = 18/21
Scale Factor = 18/21

We could leave the answer like that, but we have also converted the answer to its simplest fraction form and to decimal form:

Fraction answer = 6/7
Decimal answer ≈ 0.857143

You may also be interested to know that we verified that 21 × 6/7 = 18 is true, which means that our answer is correct. Also, note that since 21 is greater than 18, this is a Reduction Scale Factor.

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Scale Factor of 21 and 19
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