Pre-Algebra Workbook 9: Measurement & Unit Conversions

Use the fact that $1$ foot $= 12$ inches. Multiply the number of feet by $12$ to get inches.

Since $1$ foot $= 12$ inches,

$$4 \text{ ft} = 4 \times 12 \text{ in} = 48 \text{ in}$$

So $4$ feet is $48$ inches.

The correct choice is C. $48$ inches.

Again use $1$ foot $= 12$ inches. Divide the number of inches by $12$ to get feet.

Use the relationship $1$ foot $= 12$ inches.

$$72 \text{ in} \div 12 = 6 \text{ ft}$$

So $72$ inches is $6$ feet.

The correct choice is B. $6$ feet.

Use $1$ yard $= 3$ feet. Multiply the number of yards by $3$ to get feet.

Since $1$ yard $= 3$ feet,

$$3 \text{ yd} = 3 \times 3 \text{ ft} = 9 \text{ ft}$$

So $3$ yards is $9$ feet.

The correct choice is A. $9$ feet.

There are $60$ minutes in $1$ hour. Multiply the number of hours by $60$ to get minutes.

Use $1$ hour $= 60$ minutes.

$$2.5 \text{ h} = 2.5 \times 60 \text{ min}$$

Compute $2.5 \times 60$

$$2.5 \times 60 = 150$$

So $2.5$ hours is $150$ minutes.

The correct choice is D. $150$ minutes.

There are $60$ minutes in an hour. Divide $135$ by $60$ to find how many full hours fit, and use the remainder as minutes.

Divide $135$ by $60$

$$135 \div 60 = 2 \text{ remainder } 15$$

So $135$ minutes is $2$ full hours and $15$ extra minutes.

Therefore, $135$ minutes $= 2$ hours $15$ minutes.

The correct choice is B. $2$ hours $15$ minutes.

Add hours to hours and minutes to minutes. If the minutes add to $60$ or more, convert $60$ minutes to $1$ hour and adjust.

Add the hours and minutes separately:

• Hours: $1 + 2 = 3$
• Minutes: $35 + 50 = 85$

Since $85$ minutes is more than $60$ minutes, convert:

$$85 \text{ min} = 60 \text{ min} + 25 \text{ min} = 1 \text{ hour } 25 \text{ minutes}$$

Add the extra hour to the hours total:

$$3 \text{ hours} + 1 \text{ hour} = 4 \text{ hours}$$

So the total time is $4$ hours $25$ minutes.

The correct choice is C. $4$ hours $25$ minutes.

You can borrow $1$ hour as $60$ minutes. Rewrite $2$ hours $5$ minutes as $1$ hour $65$ minutes, then subtract.

Rewrite $2$ hours $5$ minutes by borrowing $1$ hour as $60$ minutes:

$$2 \text{ h } 5 \text{ min} = 1 \text{ h } (60 + 5) \text{ min} = 1 \text{ h } 65 \text{ min}$$

Now subtract $47$ minutes:

$$65 \text{ min} - 47 \text{ min} = 18 \text{ min}$$

The hours stay at $1$

So the result is $1$ hour $18$ minutes.

The correct choice is A. $1$ hour $18$ minutes.

Multiply the number of kilometers by $0.62$ miles per kilometer to convert to miles.

Use the conversion $1$ kilometer $\approx 0.62$ miles:

$$10 \text{ km} \times 0.62 \dfrac{\text{miles}}{\text{km}} = 6.2 \text{ miles}$$

So the runner traveled about $6.2$ miles.

The correct choice is D. $6.2$ miles.

The perimeter of a rectangle is $2 \times (\text{length} + \text{width})$ Add the length and width, then multiply by $2$

Use the perimeter formula for a rectangle:

$$P = 2(\text{length} + \text{width})$$

Substitute length $= 12$ ft and width $= 8$ ft:

$$P = 2(12 + 8) = 2 \times 20 = 40 \text{ ft}$$

So the perimeter is $40$ feet.

The correct choice is C. $40$ feet.

Add the two times in minutes, then convert the total minutes to hours and minutes using $60$ minutes $= 1$ hour.

Add the lengths of the two episodes:

$$42 \text{ min} + 38 \text{ min} = 80 \text{ min}$$

Convert $80$ minutes to hours and minutes:

$$80 \div 60 = 1 \text{ hour } 20 \text{ minutes}$$

So Kurt spends $1$ hour $20$ minutes watching in total.

The correct choice is B. $1$ hour $20$ minutes.