Sabes que 3 pies [tex]$= 1 \text{ yd}$[/tex]. Divide [tex]$6 \div 3$[/tex]. Por tanto, 6 pies [tex]$= 2 \text{ yd}$[/tex].

Sabes que 1 pie [tex]$= 12$[/tex] pulgadas. Multiplica [tex]$2 \times 12$[/tex]. Por tanto, 2 pies [tex]$= 24$[/tex] pulgadas.

Para 1 a 9, convierte las unidades de longitud:

1. 12 pies [tex]$=$[/tex] [tex]$\qquad$[/tex] yd
2. [tex]$2 \text{ mi} =$[/tex] [tex]$\qquad$[/tex] 3520 yd
3. [tex]$3 \text{ mi} =$[/tex] [tex]$\qquad$[/tex] 15840 pies
4. 7 pies [tex]$=$[/tex] [tex]$\qquad$[/tex] pulgadas
5. 108 pulgadas [tex]$=$[/tex] [tex]$\qquad$[/tex] pies
6. 2 pies 3 pulgadas [tex]$=$[/tex] [tex]$\qquad$[/tex] pulgadas
7. 45 pulgadas [tex]$=$[/tex] [tex]$\qquad$[/tex] yd y [tex]$\qquad$[/tex] pulgadas

We start with the following conversion factors:

- [tex]$3$[/tex] feet (pies) [tex]$= 1$[/tex] yard (yd)
- [tex]$1$[/tex] foot (pie) [tex]$= 12$[/tex] inches (pulgs)
- [tex]$1$[/tex] mile (mi) [tex]$= 5280$[/tex] feet (pies)
- [tex]$1$[/tex] mile (mi) [tex]$= 1760$[/tex] yards (yd)
- (Also, [tex]$1$[/tex] yard [tex]$= 3$[/tex] feet, which implies [tex]$1$[/tex] yard [tex]$= 3 \times 12 = 36$[/tex] pulgs)

We will use these facts to work through each item.

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1. Convert [tex]$12$[/tex] feet to yards.

Since [tex]$3$[/tex] feet [tex]$= 1$[/tex] yard, we have:

[tex]$$
12\text{ feet} \div 3 = 4\text{ yards.}
$$[/tex]

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2. Convert [tex]$2$[/tex] miles to yards.

Knowing that [tex]$1$[/tex] mile [tex]$= 1760$[/tex] yards:

[tex]$$
2\text{ miles} \times 1760 = 3520\text{ yards.}
$$[/tex]

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5. Convert [tex]$3$[/tex] miles to feet.

Since [tex]$1$[/tex] mile [tex]$= 5280$[/tex] feet:

[tex]$$
3\text{ miles} \times 5280 = 15840\text{ feet.}
$$[/tex]

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6. Convert [tex]$108$[/tex] pulgs to feet.

Given that [tex]$1$[/tex] foot [tex]$= 12$[/tex] pulgs, we get:

[tex]$$
108\text{ pulgs} \div 12 = 9\text{ feet.}
$$[/tex]

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4. Convert [tex]$7$[/tex] feet both to pulgs and yards.

(a) To convert to pulgs, since [tex]$1$[/tex] foot [tex]$= 12$[/tex] pulgs:

[tex]$$
7\text{ feet} \times 12 = 84\text{ pulgs.}
$$[/tex]

(b) To convert to yards, use the fact that [tex]$3$[/tex] feet [tex]$= 1$[/tex] yard:

[tex]$$
7\text{ feet} \div 3 \approx 2.3333\text{ yards.}
$$[/tex]

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8. Convert [tex]$2$[/tex] feet and [tex]$3$[/tex] pulgs to pulgs.

First, convert the feet to pulgs:

[tex]$$
2\text{ feet} \times 12 = 24\text{ pulgs.}
$$[/tex]

Then add the extra [tex]$3$[/tex] pulgs:

[tex]$$
24 + 3 = 27\text{ pulgs.}
$$[/tex]

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9. Express [tex]$45$[/tex] pulgs in yards and pulgs.

Since [tex]$1$[/tex] yard [tex]$= 36$[/tex] pulgs, first find how many whole yards are contained in [tex]$45$[/tex] pulgs:

[tex]$$
45 \div 36 = 1\text{ yard} \quad (\text{since } 36 \times 1 = 36)
$$[/tex]

The remaining pulgs will be:

[tex]$$
45 - 36 = 9\text{ pulgs.}
$$[/tex]

So, [tex]$45$[/tex] pulgs [tex]$= 1$[/tex] yard and [tex]$9$[/tex] pulgs.

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To summarize, the answers are:

1. [tex]$12$[/tex] feet [tex]$= 4$[/tex] yards
2. [tex]$2$[/tex] miles [tex]$= 3520$[/tex] yards
5. [tex]$3$[/tex] miles [tex]$= 15840$[/tex] feet
6. [tex]$108$[/tex] pulgs [tex]$= 9$[/tex] feet
4. [tex]$7$[/tex] feet [tex]$= 84$[/tex] pulgs and approximately [tex]$2.3333$[/tex] yards
8. [tex]$2$[/tex] feet [tex]$3$[/tex] pulgs [tex]$= 27$[/tex] pulgs
9. [tex]$45$[/tex] pulgs [tex]$= 1$[/tex] yard and [tex]$9$[/tex] pulgs