Select all ratios equivalent to [tex][tex]$7: 9$[/tex][/tex].

A. [tex][tex]$5: 15$[/tex][/tex]
B. [tex][tex]$84: 108$[/tex][/tex]
C. [tex][tex]$27: 54$[/tex][/tex]



Answer :

To determine which of the given ratios is equivalent to [tex]\(7 : 9\)[/tex], we'll follow these steps:

1. Simplify each given ratio to its simplest form:
- A ratio is in its simplest form when the greatest common divisor (GCD) of both numbers in the ratio is 1.

2. Compare the simplified form of each ratio to [tex]\(7 : 9\)[/tex]:
- If the simplified form of any ratio matches [tex]\(7 : 9\)[/tex], then that ratio is equivalent to [tex]\(7 : 9\)[/tex].

### Step-by-Step Solution

#### Simplifying [tex]\(5 : 15\)[/tex]:
1. Find the GCD of 5 and 15. The GCD of 5 and 15 is 5.
2. Divide both terms of the ratio by their GCD:
[tex]\[ \frac{5}{5} : \frac{15}{5} = 1 : 3 \][/tex]
3. The simplified form of [tex]\(5 : 15\)[/tex] is [tex]\(1 : 3\)[/tex].

#### Simplifying [tex]\(84 : 108\)[/tex]:
1. Find the GCD of 84 and 108. The GCD of 84 and 108 is 12.
2. Divide both terms of the ratio by their GCD:
[tex]\[ \frac{84}{12} : \frac{108}{12} = 7 : 9 \][/tex]
3. The simplified form of [tex]\(84 : 108\)[/tex] is [tex]\(7 : 9\)[/tex].

#### Simplifying [tex]\(27 : 54\)[/tex]:
1. Find the GCD of 27 and 54. The GCD of 27 and 54 is 27.
2. Divide both terms of the ratio by their GCD:
[tex]\[ \frac{27}{27} : \frac{54}{27} = 1 : 2 \][/tex]
3. The simplified form of [tex]\(27 : 54\)[/tex] is [tex]\(1 : 2\)[/tex].

### Comparing Simplified Ratios:
- The simplified form of [tex]\(5 : 15\)[/tex] is [tex]\(1 : 3\)[/tex], which is not equivalent to [tex]\(7 : 9\)[/tex].
- The simplified form of [tex]\(84 : 108\)[/tex] is [tex]\(7 : 9\)[/tex], which is equivalent to [tex]\(7 : 9\)[/tex].
- The simplified form of [tex]\(27 : 54\)[/tex] is [tex]\(1 : 2\)[/tex], which is not equivalent to [tex]\(7 : 9\)[/tex].

### Conclusion
Among the given ratios, only [tex]\(84 : 108\)[/tex] is equivalent to [tex]\(7 : 9\)[/tex]. Thus, the ratio equivalent to [tex]\(7 : 9\)[/tex] is:

[tex]\[ 84 : 108 \][/tex]