Write the following proportion using colons. 7 is to 21 as 3 is to 9.
a. 7: 21 = 3: 9
b. 7: 3 = 21: 9
c. 21: 7 = 3: 9
d. 7: 21 = 9: 3

Option A.

Step-by-step explanation:

There are two fraction given in this question and we have to write the proportion using colon.

Visually fractions and are different but when we simplify these fractions we get the actual relation between them.

We simplify first.

By dividing from 7 in the numerator and denominator we get

similarly we simplify the fraction

By dividing numerator and denominator by 3

Now we can say that both the fractions are equal.

So the ratio will be 7 : 21 = 3 : 9

Option A. will be the answer.

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