Question

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

Answer 1

The answer is 7:21 = 3:9.

Answer 2

Answer:

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 $\frac{7}{21}$ and $\frac{3}{9}$ are different but when we simplify these fractions we get the actual relation between them.

We simplify $\frac{7}{21}$ first.

By dividing from 7 in the numerator and denominator we get

$\frac{\frac{7}{7}}{\frac{21}{7}}=\frac{1}{3}$

similarly we simplify the fraction $\frac{3}{9}$

By dividing numerator and denominator by 3

$\frac{\frac{3}{3} }{\frac{9}{3} }=\frac{1}{3}$

Now we can say that both the fractions are equal.

$\frac{7}{21}=\frac{3}{9}=\frac{1}{3}$

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

Option A. will be the answer.